Dataintro-Pandas.ipynb

{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Pandas Basics\n",
    "\n",
    "A high-level overview of the [Pandas](https://pandas.pydata.org) library."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [],
   "source": [
    "%matplotlib inline\n",
    "import matplotlib.pyplot as plt\n",
    "import seaborn as sns\n",
    "import numpy as np\n",
    "import pandas as pd\n",
    "\n",
    "plt.style.use('fivethirtyeight')\n",
    "sns.set_context(\"notebook\")"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Reading in DataFrames from Files"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Pandas has a number of very useful file reading tools. You can see them enumerated by typing \"pd.re\" and pressing tab. We'll be using read_csv today. "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {
    "scrolled": true
   },
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div>\n",
       "<style scoped>\n",
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       "\n",
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       "    }\n",
       "</style>\n",
       "<table border=\"1\" class=\"dataframe\">\n",
       "  <thead>\n",
       "    <tr style=\"text-align: right;\">\n",
       "      <th></th>\n",
       "      <th>Candidate</th>\n",
       "      <th>Party</th>\n",
       "      <th>%</th>\n",
       "      <th>Year</th>\n",
       "      <th>Result</th>\n",
       "    </tr>\n",
       "  </thead>\n",
       "  <tbody>\n",
       "    <tr>\n",
       "      <th>0</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "      <td>50.7</td>\n",
       "      <td>1980</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1</th>\n",
       "      <td>Carter</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>41.0</td>\n",
       "      <td>1980</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2</th>\n",
       "      <td>Anderson</td>\n",
       "      <td>Independent</td>\n",
       "      <td>6.6</td>\n",
       "      <td>1980</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>3</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "      <td>58.8</td>\n",
       "      <td>1984</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>4</th>\n",
       "      <td>Mondale</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>37.6</td>\n",
       "      <td>1984</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>5</th>\n",
       "      <td>Bush</td>\n",
       "      <td>Republican</td>\n",
       "      <td>53.4</td>\n",
       "      <td>1988</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>6</th>\n",
       "      <td>Dukakis</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>45.6</td>\n",
       "      <td>1988</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>7</th>\n",
       "      <td>Clinton</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>43.0</td>\n",
       "      <td>1992</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>8</th>\n",
       "      <td>Bush</td>\n",
       "      <td>Republican</td>\n",
       "      <td>37.4</td>\n",
       "      <td>1992</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>9</th>\n",
       "      <td>Perot</td>\n",
       "      <td>Independent</td>\n",
       "      <td>18.9</td>\n",
       "      <td>1992</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>10</th>\n",
       "      <td>Clinton</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>49.2</td>\n",
       "      <td>1996</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>11</th>\n",
       "      <td>Dole</td>\n",
       "      <td>Republican</td>\n",
       "      <td>40.7</td>\n",
       "      <td>1996</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>12</th>\n",
       "      <td>Perot</td>\n",
       "      <td>Independent</td>\n",
       "      <td>8.4</td>\n",
       "      <td>1996</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>13</th>\n",
       "      <td>Gore</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>48.4</td>\n",
       "      <td>2000</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>14</th>\n",
       "      <td>Bush</td>\n",
       "      <td>Republican</td>\n",
       "      <td>47.9</td>\n",
       "      <td>2000</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>15</th>\n",
       "      <td>Kerry</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>48.3</td>\n",
       "      <td>2004</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>16</th>\n",
       "      <td>Bush</td>\n",
       "      <td>Republican</td>\n",
       "      <td>50.7</td>\n",
       "      <td>2004</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>17</th>\n",
       "      <td>Obama</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>52.9</td>\n",
       "      <td>2008</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>18</th>\n",
       "      <td>McCain</td>\n",
       "      <td>Republican</td>\n",
       "      <td>45.7</td>\n",
       "      <td>2008</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>19</th>\n",
       "      <td>Obama</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>51.1</td>\n",
       "      <td>2012</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>20</th>\n",
       "      <td>Romney</td>\n",
       "      <td>Republican</td>\n",
       "      <td>47.2</td>\n",
       "      <td>2012</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>21</th>\n",
       "      <td>Clinton</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>48.2</td>\n",
       "      <td>2016</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>22</th>\n",
       "      <td>Trump</td>\n",
       "      <td>Republican</td>\n",
       "      <td>46.1</td>\n",
       "      <td>2016</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "  </tbody>\n",
       "</table>\n",
       "</div>"
      ],
      "text/plain": [
       "   Candidate        Party     %  Year Result\n",
       "0     Reagan   Republican  50.7  1980    win\n",
       "1     Carter   Democratic  41.0  1980   loss\n",
       "2   Anderson  Independent   6.6  1980   loss\n",
       "3     Reagan   Republican  58.8  1984    win\n",
       "4    Mondale   Democratic  37.6  1984   loss\n",
       "5       Bush   Republican  53.4  1988    win\n",
       "6    Dukakis   Democratic  45.6  1988   loss\n",
       "7    Clinton   Democratic  43.0  1992    win\n",
       "8       Bush   Republican  37.4  1992   loss\n",
       "9      Perot  Independent  18.9  1992   loss\n",
       "10   Clinton   Democratic  49.2  1996    win\n",
       "11      Dole   Republican  40.7  1996   loss\n",
       "12     Perot  Independent   8.4  1996   loss\n",
       "13      Gore   Democratic  48.4  2000   loss\n",
       "14      Bush   Republican  47.9  2000    win\n",
       "15     Kerry   Democratic  48.3  2004   loss\n",
       "16      Bush   Republican  50.7  2004    win\n",
       "17     Obama   Democratic  52.9  2008    win\n",
       "18    McCain   Republican  45.7  2008   loss\n",
       "19     Obama   Democratic  51.1  2012    win\n",
       "20    Romney   Republican  47.2  2012   loss\n",
       "21   Clinton   Democratic  48.2  2016   loss\n",
       "22     Trump   Republican  46.1  2016    win"
      ]
     },
     "execution_count": 2,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "elections = pd.read_csv(\"sampledata/elections.csv\")\n",
    "elections # if we end a cell with an expression or variable name, the result will print"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "We can use the head command to return only a few rows of a dataframe."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [
    {
     "data": {
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       "    <tr style=\"text-align: right;\">\n",
       "      <th></th>\n",
       "      <th>Candidate</th>\n",
       "      <th>Party</th>\n",
       "      <th>%</th>\n",
       "      <th>Year</th>\n",
       "      <th>Result</th>\n",
       "    </tr>\n",
       "  </thead>\n",
       "  <tbody>\n",
       "    <tr>\n",
       "      <th>0</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "      <td>50.7</td>\n",
       "      <td>1980</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1</th>\n",
       "      <td>Carter</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>41.0</td>\n",
       "      <td>1980</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2</th>\n",
       "      <td>Anderson</td>\n",
       "      <td>Independent</td>\n",
       "      <td>6.6</td>\n",
       "      <td>1980</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>3</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "      <td>58.8</td>\n",
       "      <td>1984</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>4</th>\n",
       "      <td>Mondale</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>37.6</td>\n",
       "      <td>1984</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>5</th>\n",
       "      <td>Bush</td>\n",
       "      <td>Republican</td>\n",
       "      <td>53.4</td>\n",
       "      <td>1988</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>6</th>\n",
       "      <td>Dukakis</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>45.6</td>\n",
       "      <td>1988</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>7</th>\n",
       "      <td>Clinton</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>43.0</td>\n",
       "      <td>1992</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>8</th>\n",
       "      <td>Bush</td>\n",
       "      <td>Republican</td>\n",
       "      <td>37.4</td>\n",
       "      <td>1992</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>9</th>\n",
       "      <td>Perot</td>\n",
       "      <td>Independent</td>\n",
       "      <td>18.9</td>\n",
       "      <td>1992</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "  </tbody>\n",
       "</table>\n",
       "</div>"
      ],
      "text/plain": [
       "  Candidate        Party     %  Year Result\n",
       "0    Reagan   Republican  50.7  1980    win\n",
       "1    Carter   Democratic  41.0  1980   loss\n",
       "2  Anderson  Independent   6.6  1980   loss\n",
       "3    Reagan   Republican  58.8  1984    win\n",
       "4   Mondale   Democratic  37.6  1984   loss\n",
       "5      Bush   Republican  53.4  1988    win\n",
       "6   Dukakis   Democratic  45.6  1988   loss\n",
       "7   Clinton   Democratic  43.0  1992    win\n",
       "8      Bush   Republican  37.4  1992   loss\n",
       "9     Perot  Independent  18.9  1992   loss"
      ]
     },
     "execution_count": 3,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "elections.head(10)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "There is also a tail command."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {},
   "outputs": [
    {
     "data": {
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       "  <thead>\n",
       "    <tr style=\"text-align: right;\">\n",
       "      <th></th>\n",
       "      <th>Candidate</th>\n",
       "      <th>Party</th>\n",
       "      <th>%</th>\n",
       "      <th>Year</th>\n",
       "      <th>Result</th>\n",
       "    </tr>\n",
       "  </thead>\n",
       "  <tbody>\n",
       "    <tr>\n",
       "      <th>16</th>\n",
       "      <td>Bush</td>\n",
       "      <td>Republican</td>\n",
       "      <td>50.7</td>\n",
       "      <td>2004</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>17</th>\n",
       "      <td>Obama</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>52.9</td>\n",
       "      <td>2008</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>18</th>\n",
       "      <td>McCain</td>\n",
       "      <td>Republican</td>\n",
       "      <td>45.7</td>\n",
       "      <td>2008</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>19</th>\n",
       "      <td>Obama</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>51.1</td>\n",
       "      <td>2012</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>20</th>\n",
       "      <td>Romney</td>\n",
       "      <td>Republican</td>\n",
       "      <td>47.2</td>\n",
       "      <td>2012</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>21</th>\n",
       "      <td>Clinton</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>48.2</td>\n",
       "      <td>2016</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>22</th>\n",
       "      <td>Trump</td>\n",
       "      <td>Republican</td>\n",
       "      <td>46.1</td>\n",
       "      <td>2016</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "  </tbody>\n",
       "</table>\n",
       "</div>"
      ],
      "text/plain": [
       "   Candidate       Party     %  Year Result\n",
       "16      Bush  Republican  50.7  2004    win\n",
       "17     Obama  Democratic  52.9  2008    win\n",
       "18    McCain  Republican  45.7  2008   loss\n",
       "19     Obama  Democratic  51.1  2012    win\n",
       "20    Romney  Republican  47.2  2012   loss\n",
       "21   Clinton  Democratic  48.2  2016   loss\n",
       "22     Trump  Republican  46.1  2016    win"
      ]
     },
     "execution_count": 4,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "elections.tail(7)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "The read_csv command lets us specify a column to use an index. For example, we could have used Year as the index."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {},
   "outputs": [
    {
     "data": {
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       "<table border=\"1\" class=\"dataframe\">\n",
       "  <thead>\n",
       "    <tr style=\"text-align: right;\">\n",
       "      <th></th>\n",
       "      <th>Candidate</th>\n",
       "      <th>Party</th>\n",
       "      <th>%</th>\n",
       "      <th>Result</th>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>Year</th>\n",
       "      <th></th>\n",
       "      <th></th>\n",
       "      <th></th>\n",
       "      <th></th>\n",
       "    </tr>\n",
       "  </thead>\n",
       "  <tbody>\n",
       "    <tr>\n",
       "      <th>1980</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "      <td>50.7</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1980</th>\n",
       "      <td>Carter</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>41.0</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1980</th>\n",
       "      <td>Anderson</td>\n",
       "      <td>Independent</td>\n",
       "      <td>6.6</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1984</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "      <td>58.8</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1984</th>\n",
       "      <td>Mondale</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>37.6</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "  </tbody>\n",
       "</table>\n",
       "</div>"
      ],
      "text/plain": [
       "     Candidate        Party     % Result\n",
       "Year                                    \n",
       "1980    Reagan   Republican  50.7    win\n",
       "1980    Carter   Democratic  41.0   loss\n",
       "1980  Anderson  Independent   6.6   loss\n",
       "1984    Reagan   Republican  58.8    win\n",
       "1984   Mondale   Democratic  37.6   loss"
      ]
     },
     "execution_count": 5,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "elections_year_index = pd.read_csv(\"sampledata/elections.csv\", index_col = \"Year\")\n",
    "elections_year_index.head(5)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Alternately, we could have used the set_index commmand."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div>\n",
       "<style scoped>\n",
       "    .dataframe tbody tr th:only-of-type {\n",
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       "<table border=\"1\" class=\"dataframe\">\n",
       "  <thead>\n",
       "    <tr style=\"text-align: right;\">\n",
       "      <th></th>\n",
       "      <th>Candidate</th>\n",
       "      <th>%</th>\n",
       "      <th>Year</th>\n",
       "      <th>Result</th>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>Party</th>\n",
       "      <th></th>\n",
       "      <th></th>\n",
       "      <th></th>\n",
       "      <th></th>\n",
       "    </tr>\n",
       "  </thead>\n",
       "  <tbody>\n",
       "    <tr>\n",
       "      <th>Republican</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>50.7</td>\n",
       "      <td>1980</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>Democratic</th>\n",
       "      <td>Carter</td>\n",
       "      <td>41.0</td>\n",
       "      <td>1980</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>Independent</th>\n",
       "      <td>Anderson</td>\n",
       "      <td>6.6</td>\n",
       "      <td>1980</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>Republican</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>58.8</td>\n",
       "      <td>1984</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>Democratic</th>\n",
       "      <td>Mondale</td>\n",
       "      <td>37.6</td>\n",
       "      <td>1984</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "  </tbody>\n",
       "</table>\n",
       "</div>"
      ],
      "text/plain": [
       "            Candidate     %  Year Result\n",
       "Party                                   \n",
       "Republican     Reagan  50.7  1980    win\n",
       "Democratic     Carter  41.0  1980   loss\n",
       "Independent  Anderson   6.6  1980   loss\n",
       "Republican     Reagan  58.8  1984    win\n",
       "Democratic    Mondale  37.6  1984   loss"
      ]
     },
     "execution_count": 6,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "elections_party_index = elections.set_index(\"Party\")\n",
    "elections_party_index.head(5)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "The set_index command (along with all other data frame methods) does not modify the dataframe. That is, the original \"elections\" is untouched. Note: There is a flag called \"inplace\" which does modify the calling dataframe."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div>\n",
       "<style scoped>\n",
       "    .dataframe tbody tr th:only-of-type {\n",
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       "<table border=\"1\" class=\"dataframe\">\n",
       "  <thead>\n",
       "    <tr style=\"text-align: right;\">\n",
       "      <th></th>\n",
       "      <th>Candidate</th>\n",
       "      <th>Party</th>\n",
       "      <th>%</th>\n",
       "      <th>Year</th>\n",
       "      <th>Result</th>\n",
       "    </tr>\n",
       "  </thead>\n",
       "  <tbody>\n",
       "    <tr>\n",
       "      <th>0</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "      <td>50.7</td>\n",
       "      <td>1980</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1</th>\n",
       "      <td>Carter</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>41.0</td>\n",
       "      <td>1980</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2</th>\n",
       "      <td>Anderson</td>\n",
       "      <td>Independent</td>\n",
       "      <td>6.6</td>\n",
       "      <td>1980</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>3</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "      <td>58.8</td>\n",
       "      <td>1984</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>4</th>\n",
       "      <td>Mondale</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>37.6</td>\n",
       "      <td>1984</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "  </tbody>\n",
       "</table>\n",
       "</div>"
      ],
      "text/plain": [
       "  Candidate        Party     %  Year Result\n",
       "0    Reagan   Republican  50.7  1980    win\n",
       "1    Carter   Democratic  41.0  1980   loss\n",
       "2  Anderson  Independent   6.6  1980   loss\n",
       "3    Reagan   Republican  58.8  1984    win\n",
       "4   Mondale   Democratic  37.6  1984   loss"
      ]
     },
     "execution_count": 7,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "elections.head() #the index remains unchanged"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "By contrast, column names are ideally unique. If we try to read in a file for which column names are not unique, Pandas will automatically rename any duplicates."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## The [] Operator"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "The DataFrame class has an indexing operator [] that lets you do a variety of different things. If your provide a String to the [] operator, you get back a Series corresponding to the requested label."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div>\n",
       "<style scoped>\n",
       "    .dataframe tbody tr th:only-of-type {\n",
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       "\n",
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       "    }\n",
       "\n",
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       "</style>\n",
       "<table border=\"1\" class=\"dataframe\">\n",
       "  <thead>\n",
       "    <tr style=\"text-align: right;\">\n",
       "      <th></th>\n",
       "      <th>Candidate</th>\n",
       "      <th>Party</th>\n",
       "      <th>%</th>\n",
       "      <th>Result</th>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>Year</th>\n",
       "      <th></th>\n",
       "      <th></th>\n",
       "      <th></th>\n",
       "      <th></th>\n",
       "    </tr>\n",
       "  </thead>\n",
       "  <tbody>\n",
       "    <tr>\n",
       "      <th>1980</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "      <td>50.7</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1980</th>\n",
       "      <td>Carter</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>41.0</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1980</th>\n",
       "      <td>Anderson</td>\n",
       "      <td>Independent</td>\n",
       "      <td>6.6</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1984</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "      <td>58.8</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1984</th>\n",
       "      <td>Mondale</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>37.6</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1988</th>\n",
       "      <td>Bush</td>\n",
       "      <td>Republican</td>\n",
       "      <td>53.4</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "  </tbody>\n",
       "</table>\n",
       "</div>"
      ],
      "text/plain": [
       "     Candidate        Party     % Result\n",
       "Year                                    \n",
       "1980    Reagan   Republican  50.7    win\n",
       "1980    Carter   Democratic  41.0   loss\n",
       "1980  Anderson  Independent   6.6   loss\n",
       "1984    Reagan   Republican  58.8    win\n",
       "1984   Mondale   Democratic  37.6   loss\n",
       "1988      Bush   Republican  53.4    win"
      ]
     },
     "execution_count": 8,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "elections_year_index.head(6)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "Year\n",
       "1980      Reagan\n",
       "1980      Carter\n",
       "1980    Anderson\n",
       "1984      Reagan\n",
       "1984     Mondale\n",
       "1988        Bush\n",
       "Name: Candidate, dtype: object"
      ]
     },
     "execution_count": 9,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "elections_year_index[\"Candidate\"].head(6)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "The [] operator also accepts a list of strings. In this case, you get back a DataFrame corresponding to the requested strings."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 10,
   "metadata": {
    "scrolled": true
   },
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div>\n",
       "<style scoped>\n",
       "    .dataframe tbody tr th:only-of-type {\n",
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       "      <th></th>\n",
       "      <th>Candidate</th>\n",
       "      <th>Party</th>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>Year</th>\n",
       "      <th></th>\n",
       "      <th></th>\n",
       "    </tr>\n",
       "  </thead>\n",
       "  <tbody>\n",
       "    <tr>\n",
       "      <th>1980</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1980</th>\n",
       "      <td>Carter</td>\n",
       "      <td>Democratic</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1980</th>\n",
       "      <td>Anderson</td>\n",
       "      <td>Independent</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1984</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1984</th>\n",
       "      <td>Mondale</td>\n",
       "      <td>Democratic</td>\n",
       "    </tr>\n",
       "  </tbody>\n",
       "</table>\n",
       "</div>"
      ],
      "text/plain": [
       "     Candidate        Party\n",
       "Year                       \n",
       "1980    Reagan   Republican\n",
       "1980    Carter   Democratic\n",
       "1980  Anderson  Independent\n",
       "1984    Reagan   Republican\n",
       "1984   Mondale   Democratic"
      ]
     },
     "execution_count": 10,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "elections_year_index[[\"Candidate\", \"Party\"]].head()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "A list of one label also returns a DataFrame. This can be handy if you want your results as a DataFrame, not a series."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 11,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div>\n",
       "<style scoped>\n",
       "    .dataframe tbody tr th:only-of-type {\n",
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       "\n",
       "    .dataframe tbody tr th {\n",
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       "    }\n",
       "\n",
       "    .dataframe thead th {\n",
       "        text-align: right;\n",
       "    }\n",
       "</style>\n",
       "<table border=\"1\" class=\"dataframe\">\n",
       "  <thead>\n",
       "    <tr style=\"text-align: right;\">\n",
       "      <th></th>\n",
       "      <th>Candidate</th>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>Year</th>\n",
       "      <th></th>\n",
       "    </tr>\n",
       "  </thead>\n",
       "  <tbody>\n",
       "    <tr>\n",
       "      <th>1980</th>\n",
       "      <td>Reagan</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1980</th>\n",
       "      <td>Carter</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1980</th>\n",
       "      <td>Anderson</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1984</th>\n",
       "      <td>Reagan</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1984</th>\n",
       "      <td>Mondale</td>\n",
       "    </tr>\n",
       "  </tbody>\n",
       "</table>\n",
       "</div>"
      ],
      "text/plain": [
       "     Candidate\n",
       "Year          \n",
       "1980    Reagan\n",
       "1980    Carter\n",
       "1980  Anderson\n",
       "1984    Reagan\n",
       "1984   Mondale"
      ]
     },
     "execution_count": 11,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "elections_year_index[[\"Candidate\"]].head()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Note that we can also use the to_frame method to turn a Series into a DataFrame."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 12,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div>\n",
       "<style scoped>\n",
       "    .dataframe tbody tr th:only-of-type {\n",
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       "\n",
       "    .dataframe tbody tr th {\n",
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       "    }\n",
       "\n",
       "    .dataframe thead th {\n",
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       "</style>\n",
       "<table border=\"1\" class=\"dataframe\">\n",
       "  <thead>\n",
       "    <tr style=\"text-align: right;\">\n",
       "      <th></th>\n",
       "      <th>Candidate</th>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>Year</th>\n",
       "      <th></th>\n",
       "    </tr>\n",
       "  </thead>\n",
       "  <tbody>\n",
       "    <tr>\n",
       "      <th>1980</th>\n",
       "      <td>Reagan</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1980</th>\n",
       "      <td>Carter</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1980</th>\n",
       "      <td>Anderson</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1984</th>\n",
       "      <td>Reagan</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1984</th>\n",
       "      <td>Mondale</td>\n",
       "    </tr>\n",
       "  </tbody>\n",
       "</table>\n",
       "</div>"
      ],
      "text/plain": [
       "     Candidate\n",
       "Year          \n",
       "1980    Reagan\n",
       "1980    Carter\n",
       "1980  Anderson\n",
       "1984    Reagan\n",
       "1984   Mondale"
      ]
     },
     "execution_count": 12,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "elections_year_index[\"Candidate\"].to_frame().head()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "The [] operator also accepts numerical slices as arguments. In this case, we are indexing by row, not column!"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 13,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div>\n",
       "<style scoped>\n",
       "    .dataframe tbody tr th:only-of-type {\n",
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       "    .dataframe tbody tr th {\n",
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       "\n",
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       "<table border=\"1\" class=\"dataframe\">\n",
       "  <thead>\n",
       "    <tr style=\"text-align: right;\">\n",
       "      <th></th>\n",
       "      <th>Candidate</th>\n",
       "      <th>Party</th>\n",
       "      <th>%</th>\n",
       "      <th>Result</th>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>Year</th>\n",
       "      <th></th>\n",
       "      <th></th>\n",
       "      <th></th>\n",
       "      <th></th>\n",
       "    </tr>\n",
       "  </thead>\n",
       "  <tbody>\n",
       "    <tr>\n",
       "      <th>1980</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "      <td>50.7</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1980</th>\n",
       "      <td>Carter</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>41.0</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1980</th>\n",
       "      <td>Anderson</td>\n",
       "      <td>Independent</td>\n",
       "      <td>6.6</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "  </tbody>\n",
       "</table>\n",
       "</div>"
      ],
      "text/plain": [
       "     Candidate        Party     % Result\n",
       "Year                                    \n",
       "1980    Reagan   Republican  50.7    win\n",
       "1980    Carter   Democratic  41.0   loss\n",
       "1980  Anderson  Independent   6.6   loss"
      ]
     },
     "execution_count": 13,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "elections_year_index[0:3]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 20,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div>\n",
       "<style scoped>\n",
       "    .dataframe tbody tr th:only-of-type {\n",
       "        vertical-align: middle;\n",
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       "\n",
       "    .dataframe tbody tr th {\n",
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       "\n",
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       "</style>\n",
       "<table border=\"1\" class=\"dataframe\">\n",
       "  <thead>\n",
       "    <tr style=\"text-align: right;\">\n",
       "      <th></th>\n",
       "      <th>Candidate</th>\n",
       "      <th>Party</th>\n",
       "      <th>%</th>\n",
       "      <th>Result</th>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>Year</th>\n",
       "      <th></th>\n",
       "      <th></th>\n",
       "      <th></th>\n",
       "      <th></th>\n",
       "    </tr>\n",
       "  </thead>\n",
       "  <tbody>\n",
       "    <tr>\n",
       "      <th>1980</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "      <td>50.7</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "  </tbody>\n",
       "</table>\n",
       "</div>"
      ],
      "text/plain": [
       "     Candidate       Party     % Result\n",
       "Year                                   \n",
       "1980    Reagan  Republican  50.7    win"
      ]
     },
     "execution_count": 20,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "elections_year_index[0:1]"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "If you provide a single argument to the [] operator, it tries to use it as a name. This is true even if the argument passed to [] is an integer. "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "#elections_year_index[0] #this does not work, try uncommenting this to see it fail in action, woo"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Boolean Array Selection"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "The `[]` operator also supports array of booleans as an input. In this case, the array must be exactly as long as the number of rows. The result is a filtered version of the data frame, where only rows corresponding to True appear."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 21,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div>\n",
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       "\n",
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       "<table border=\"1\" class=\"dataframe\">\n",
       "  <thead>\n",
       "    <tr style=\"text-align: right;\">\n",
       "      <th></th>\n",
       "      <th>Candidate</th>\n",
       "      <th>Party</th>\n",
       "      <th>%</th>\n",
       "      <th>Result</th>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>Year</th>\n",
       "      <th></th>\n",
       "      <th></th>\n",
       "      <th></th>\n",
       "      <th></th>\n",
       "    </tr>\n",
       "  </thead>\n",
       "  <tbody>\n",
       "    <tr>\n",
       "      <th>1980</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "      <td>50.7</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1980</th>\n",
       "      <td>Carter</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>41.0</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1980</th>\n",
       "      <td>Anderson</td>\n",
       "      <td>Independent</td>\n",
       "      <td>6.6</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1984</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "      <td>58.8</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1984</th>\n",
       "      <td>Mondale</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>37.6</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1988</th>\n",
       "      <td>Bush</td>\n",
       "      <td>Republican</td>\n",
       "      <td>53.4</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1988</th>\n",
       "      <td>Dukakis</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>45.6</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1992</th>\n",
       "      <td>Clinton</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>43.0</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1992</th>\n",
       "      <td>Bush</td>\n",
       "      <td>Republican</td>\n",
       "      <td>37.4</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1992</th>\n",
       "      <td>Perot</td>\n",
       "      <td>Independent</td>\n",
       "      <td>18.9</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1996</th>\n",
       "      <td>Clinton</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>49.2</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1996</th>\n",
       "      <td>Dole</td>\n",
       "      <td>Republican</td>\n",
       "      <td>40.7</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1996</th>\n",
       "      <td>Perot</td>\n",
       "      <td>Independent</td>\n",
       "      <td>8.4</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2000</th>\n",
       "      <td>Gore</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>48.4</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2000</th>\n",
       "      <td>Bush</td>\n",
       "      <td>Republican</td>\n",
       "      <td>47.9</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2004</th>\n",
       "      <td>Kerry</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>48.3</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2004</th>\n",
       "      <td>Bush</td>\n",
       "      <td>Republican</td>\n",
       "      <td>50.7</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2008</th>\n",
       "      <td>Obama</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>52.9</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2008</th>\n",
       "      <td>McCain</td>\n",
       "      <td>Republican</td>\n",
       "      <td>45.7</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2012</th>\n",
       "      <td>Obama</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>51.1</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2012</th>\n",
       "      <td>Romney</td>\n",
       "      <td>Republican</td>\n",
       "      <td>47.2</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2016</th>\n",
       "      <td>Clinton</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>48.2</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2016</th>\n",
       "      <td>Trump</td>\n",
       "      <td>Republican</td>\n",
       "      <td>46.1</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "  </tbody>\n",
       "</table>\n",
       "</div>"
      ],
      "text/plain": [
       "     Candidate        Party     % Result\n",
       "Year                                    \n",
       "1980    Reagan   Republican  50.7    win\n",
       "1980    Carter   Democratic  41.0   loss\n",
       "1980  Anderson  Independent   6.6   loss\n",
       "1984    Reagan   Republican  58.8    win\n",
       "1984   Mondale   Democratic  37.6   loss\n",
       "1988      Bush   Republican  53.4    win\n",
       "1988   Dukakis   Democratic  45.6   loss\n",
       "1992   Clinton   Democratic  43.0    win\n",
       "1992      Bush   Republican  37.4   loss\n",
       "1992     Perot  Independent  18.9   loss\n",
       "1996   Clinton   Democratic  49.2    win\n",
       "1996      Dole   Republican  40.7   loss\n",
       "1996     Perot  Independent   8.4   loss\n",
       "2000      Gore   Democratic  48.4   loss\n",
       "2000      Bush   Republican  47.9    win\n",
       "2004     Kerry   Democratic  48.3   loss\n",
       "2004      Bush   Republican  50.7    win\n",
       "2008     Obama   Democratic  52.9    win\n",
       "2008    McCain   Republican  45.7   loss\n",
       "2012     Obama   Democratic  51.1    win\n",
       "2012    Romney   Republican  47.2   loss\n",
       "2016   Clinton   Democratic  48.2   loss\n",
       "2016     Trump   Republican  46.1    win"
      ]
     },
     "execution_count": 21,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "elections_year_index"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 22,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div>\n",
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       "<table border=\"1\" class=\"dataframe\">\n",
       "  <thead>\n",
       "    <tr style=\"text-align: right;\">\n",
       "      <th></th>\n",
       "      <th>Candidate</th>\n",
       "      <th>Party</th>\n",
       "      <th>%</th>\n",
       "      <th>Result</th>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>Year</th>\n",
       "      <th></th>\n",
       "      <th></th>\n",
       "      <th></th>\n",
       "      <th></th>\n",
       "    </tr>\n",
       "  </thead>\n",
       "  <tbody>\n",
       "    <tr>\n",
       "      <th>1992</th>\n",
       "      <td>Clinton</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>43.0</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1996</th>\n",
       "      <td>Clinton</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>49.2</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2000</th>\n",
       "      <td>Bush</td>\n",
       "      <td>Republican</td>\n",
       "      <td>47.9</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2016</th>\n",
       "      <td>Trump</td>\n",
       "      <td>Republican</td>\n",
       "      <td>46.1</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "  </tbody>\n",
       "</table>\n",
       "</div>"
      ],
      "text/plain": [
       "     Candidate       Party     % Result\n",
       "Year                                   \n",
       "1992   Clinton  Democratic  43.0    win\n",
       "1996   Clinton  Democratic  49.2    win\n",
       "2000      Bush  Republican  47.9    win\n",
       "2016     Trump  Republican  46.1    win"
      ]
     },
     "execution_count": 22,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "elections_year_index[[False, False, False, False, False, \n",
    "          False, False, True, False, False,\n",
    "          True, False, False, False, True,\n",
    "          False, False, False, False, False,\n",
    "          False, False, True]]"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "One very common task in Data Science is filtering. Boolean Array Selection is one way to achieve this in Pandas. We start by observing logical operators like the equality operator can be applied to Pandas Series data to generate a Boolean Array. For example, we can compare the 'Result' column to the String 'win':"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 23,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div>\n",
       "<style scoped>\n",
       "    .dataframe tbody tr th:only-of-type {\n",
       "        vertical-align: middle;\n",
       "    }\n",
       "\n",
       "    .dataframe tbody tr th {\n",
       "        vertical-align: top;\n",
       "    }\n",
       "\n",
       "    .dataframe thead th {\n",
       "        text-align: right;\n",
       "    }\n",
       "</style>\n",
       "<table border=\"1\" class=\"dataframe\">\n",
       "  <thead>\n",
       "    <tr style=\"text-align: right;\">\n",
       "      <th></th>\n",
       "      <th>Candidate</th>\n",
       "      <th>Party</th>\n",
       "      <th>%</th>\n",
       "      <th>Result</th>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>Year</th>\n",
       "      <th></th>\n",
       "      <th></th>\n",
       "      <th></th>\n",
       "      <th></th>\n",
       "    </tr>\n",
       "  </thead>\n",
       "  <tbody>\n",
       "    <tr>\n",
       "      <th>1980</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "      <td>50.7</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1980</th>\n",
       "      <td>Carter</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>41.0</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1980</th>\n",
       "      <td>Anderson</td>\n",
       "      <td>Independent</td>\n",
       "      <td>6.6</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1984</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "      <td>58.8</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1984</th>\n",
       "      <td>Mondale</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>37.6</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "  </tbody>\n",
       "</table>\n",
       "</div>"
      ],
      "text/plain": [
       "     Candidate        Party     % Result\n",
       "Year                                    \n",
       "1980    Reagan   Republican  50.7    win\n",
       "1980    Carter   Democratic  41.0   loss\n",
       "1980  Anderson  Independent   6.6   loss\n",
       "1984    Reagan   Republican  58.8    win\n",
       "1984   Mondale   Democratic  37.6   loss"
      ]
     },
     "execution_count": 23,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "elections_year_index.head(5)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 24,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "Year\n",
       "1980     True\n",
       "1980    False\n",
       "1980    False\n",
       "1984     True\n",
       "1984    False\n",
       "1988     True\n",
       "1988    False\n",
       "1992     True\n",
       "1992    False\n",
       "1992    False\n",
       "1996     True\n",
       "1996    False\n",
       "1996    False\n",
       "2000    False\n",
       "2000     True\n",
       "2004    False\n",
       "2004     True\n",
       "2008     True\n",
       "2008    False\n",
       "2012     True\n",
       "2012    False\n",
       "2016    False\n",
       "2016     True\n",
       "Name: Result, dtype: bool"
      ]
     },
     "execution_count": 24,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "iswin = elections_year_index['Result'] == 'win'\n",
    "iswin#.head(5)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "The output of the logical operator applied to the Series is another Series with the same name and index, but of datatype boolean. The entry at row #i represents the result of the application of that operator to the entry of the original Series at row #i."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Such a boolean Series can be used as an argument to the [] operator. For example, the following code creates a DataFrame of all election winners since 1980."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 25,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div>\n",
       "<style scoped>\n",
       "    .dataframe tbody tr th:only-of-type {\n",
       "        vertical-align: middle;\n",
       "    }\n",
       "\n",
       "    .dataframe tbody tr th {\n",
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       "    }\n",
       "\n",
       "    .dataframe thead th {\n",
       "        text-align: right;\n",
       "    }\n",
       "</style>\n",
       "<table border=\"1\" class=\"dataframe\">\n",
       "  <thead>\n",
       "    <tr style=\"text-align: right;\">\n",
       "      <th></th>\n",
       "      <th>Candidate</th>\n",
       "      <th>Party</th>\n",
       "      <th>%</th>\n",
       "      <th>Result</th>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>Year</th>\n",
       "      <th></th>\n",
       "      <th></th>\n",
       "      <th></th>\n",
       "      <th></th>\n",
       "    </tr>\n",
       "  </thead>\n",
       "  <tbody>\n",
       "    <tr>\n",
       "      <th>1980</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "      <td>50.7</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1984</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "      <td>58.8</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1988</th>\n",
       "      <td>Bush</td>\n",
       "      <td>Republican</td>\n",
       "      <td>53.4</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1992</th>\n",
       "      <td>Clinton</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>43.0</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1996</th>\n",
       "      <td>Clinton</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>49.2</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2000</th>\n",
       "      <td>Bush</td>\n",
       "      <td>Republican</td>\n",
       "      <td>47.9</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2004</th>\n",
       "      <td>Bush</td>\n",
       "      <td>Republican</td>\n",
       "      <td>50.7</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2008</th>\n",
       "      <td>Obama</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>52.9</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2012</th>\n",
       "      <td>Obama</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>51.1</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2016</th>\n",
       "      <td>Trump</td>\n",
       "      <td>Republican</td>\n",
       "      <td>46.1</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "  </tbody>\n",
       "</table>\n",
       "</div>"
      ],
      "text/plain": [
       "     Candidate       Party     % Result\n",
       "Year                                   \n",
       "1980    Reagan  Republican  50.7    win\n",
       "1984    Reagan  Republican  58.8    win\n",
       "1988      Bush  Republican  53.4    win\n",
       "1992   Clinton  Democratic  43.0    win\n",
       "1996   Clinton  Democratic  49.2    win\n",
       "2000      Bush  Republican  47.9    win\n",
       "2004      Bush  Republican  50.7    win\n",
       "2008     Obama  Democratic  52.9    win\n",
       "2012     Obama  Democratic  51.1    win\n",
       "2016     Trump  Republican  46.1    win"
      ]
     },
     "execution_count": 25,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "elections_year_index[iswin]"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Above, we've assigned the result of the logical operator to a new variable called `iswin`. This is uncommon. Usually, the series is created and used on the same line. Such code is a little tricky to read at first, but you'll get used to it quickly."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 26,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
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       "    <tr style=\"text-align: right;\">\n",
       "      <th></th>\n",
       "      <th>Candidate</th>\n",
       "      <th>Party</th>\n",
       "      <th>%</th>\n",
       "      <th>Result</th>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>Year</th>\n",
       "      <th></th>\n",
       "      <th></th>\n",
       "      <th></th>\n",
       "      <th></th>\n",
       "    </tr>\n",
       "  </thead>\n",
       "  <tbody>\n",
       "    <tr>\n",
       "      <th>1980</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "      <td>50.7</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1984</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "      <td>58.8</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1988</th>\n",
       "      <td>Bush</td>\n",
       "      <td>Republican</td>\n",
       "      <td>53.4</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1992</th>\n",
       "      <td>Clinton</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>43.0</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1996</th>\n",
       "      <td>Clinton</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>49.2</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2000</th>\n",
       "      <td>Bush</td>\n",
       "      <td>Republican</td>\n",
       "      <td>47.9</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2004</th>\n",
       "      <td>Bush</td>\n",
       "      <td>Republican</td>\n",
       "      <td>50.7</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2008</th>\n",
       "      <td>Obama</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>52.9</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2012</th>\n",
       "      <td>Obama</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>51.1</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2016</th>\n",
       "      <td>Trump</td>\n",
       "      <td>Republican</td>\n",
       "      <td>46.1</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "  </tbody>\n",
       "</table>\n",
       "</div>"
      ],
      "text/plain": [
       "     Candidate       Party     % Result\n",
       "Year                                   \n",
       "1980    Reagan  Republican  50.7    win\n",
       "1984    Reagan  Republican  58.8    win\n",
       "1988      Bush  Republican  53.4    win\n",
       "1992   Clinton  Democratic  43.0    win\n",
       "1996   Clinton  Democratic  49.2    win\n",
       "2000      Bush  Republican  47.9    win\n",
       "2004      Bush  Republican  50.7    win\n",
       "2008     Obama  Democratic  52.9    win\n",
       "2012     Obama  Democratic  51.1    win\n",
       "2016     Trump  Republican  46.1    win"
      ]
     },
     "execution_count": 26,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "elections_year_index[elections_year_index['Result'] == 'win']"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "We can select multiple criteria by creating multiple boolean Series and combining them using the `&` operator."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 27,
   "metadata": {},
   "outputs": [],
   "source": [
    "win50plus = (elections_year_index['Result'] == 'win') & (elections_year_index['%'] < 50)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 28,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "Year\n",
       "1980    False\n",
       "1980    False\n",
       "1980    False\n",
       "1984    False\n",
       "1984    False\n",
       "dtype: bool"
      ]
     },
     "execution_count": 28,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "win50plus.head(5)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 29,
   "metadata": {
    "scrolled": true
   },
   "outputs": [
    {
     "data": {
      "text/html": [
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       "    <tr>\n",
       "      <th>Year</th>\n",
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       "      <th></th>\n",
       "      <th></th>\n",
       "    </tr>\n",
       "  </thead>\n",
       "  <tbody>\n",
       "    <tr>\n",
       "      <th>1992</th>\n",
       "      <td>Clinton</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>43.0</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1996</th>\n",
       "      <td>Clinton</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>49.2</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2000</th>\n",
       "      <td>Bush</td>\n",
       "      <td>Republican</td>\n",
       "      <td>47.9</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2016</th>\n",
       "      <td>Trump</td>\n",
       "      <td>Republican</td>\n",
       "      <td>46.1</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "  </tbody>\n",
       "</table>\n",
       "</div>"
      ],
      "text/plain": [
       "     Candidate       Party     % Result\n",
       "Year                                   \n",
       "1992   Clinton  Democratic  43.0    win\n",
       "1996   Clinton  Democratic  49.2    win\n",
       "2000      Bush  Republican  47.9    win\n",
       "2016     Trump  Republican  46.1    win"
      ]
     },
     "execution_count": 29,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "elections_year_index[(elections_year_index['Result'] == 'win')\n",
    "          & (elections_year_index['%'] < 50)]"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "The | operator is the symbol for or."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 30,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
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       "      <th>Year</th>\n",
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       "      <th></th>\n",
       "    </tr>\n",
       "  </thead>\n",
       "  <tbody>\n",
       "    <tr>\n",
       "      <th>1980</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "      <td>50.7</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1980</th>\n",
       "      <td>Carter</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>41.0</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1984</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "      <td>58.8</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1984</th>\n",
       "      <td>Mondale</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>37.6</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1988</th>\n",
       "      <td>Bush</td>\n",
       "      <td>Republican</td>\n",
       "      <td>53.4</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1988</th>\n",
       "      <td>Dukakis</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>45.6</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1992</th>\n",
       "      <td>Clinton</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>43.0</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1992</th>\n",
       "      <td>Bush</td>\n",
       "      <td>Republican</td>\n",
       "      <td>37.4</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1996</th>\n",
       "      <td>Clinton</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>49.2</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1996</th>\n",
       "      <td>Dole</td>\n",
       "      <td>Republican</td>\n",
       "      <td>40.7</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2000</th>\n",
       "      <td>Gore</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>48.4</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2000</th>\n",
       "      <td>Bush</td>\n",
       "      <td>Republican</td>\n",
       "      <td>47.9</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2004</th>\n",
       "      <td>Kerry</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>48.3</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2004</th>\n",
       "      <td>Bush</td>\n",
       "      <td>Republican</td>\n",
       "      <td>50.7</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2008</th>\n",
       "      <td>Obama</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>52.9</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2008</th>\n",
       "      <td>McCain</td>\n",
       "      <td>Republican</td>\n",
       "      <td>45.7</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2012</th>\n",
       "      <td>Obama</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>51.1</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2012</th>\n",
       "      <td>Romney</td>\n",
       "      <td>Republican</td>\n",
       "      <td>47.2</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2016</th>\n",
       "      <td>Clinton</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>48.2</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2016</th>\n",
       "      <td>Trump</td>\n",
       "      <td>Republican</td>\n",
       "      <td>46.1</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "  </tbody>\n",
       "</table>\n",
       "</div>"
      ],
      "text/plain": [
       "     Candidate       Party     % Result\n",
       "Year                                   \n",
       "1980    Reagan  Republican  50.7    win\n",
       "1980    Carter  Democratic  41.0   loss\n",
       "1984    Reagan  Republican  58.8    win\n",
       "1984   Mondale  Democratic  37.6   loss\n",
       "1988      Bush  Republican  53.4    win\n",
       "1988   Dukakis  Democratic  45.6   loss\n",
       "1992   Clinton  Democratic  43.0    win\n",
       "1992      Bush  Republican  37.4   loss\n",
       "1996   Clinton  Democratic  49.2    win\n",
       "1996      Dole  Republican  40.7   loss\n",
       "2000      Gore  Democratic  48.4   loss\n",
       "2000      Bush  Republican  47.9    win\n",
       "2004     Kerry  Democratic  48.3   loss\n",
       "2004      Bush  Republican  50.7    win\n",
       "2008     Obama  Democratic  52.9    win\n",
       "2008    McCain  Republican  45.7   loss\n",
       "2012     Obama  Democratic  51.1    win\n",
       "2012    Romney  Republican  47.2   loss\n",
       "2016   Clinton  Democratic  48.2   loss\n",
       "2016     Trump  Republican  46.1    win"
      ]
     },
     "execution_count": 30,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "elections_year_index[(elections_year_index['Party'] == 'Republican')\n",
    "          | (elections_year_index['Party'] == \"Democratic\")]"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "If we have multiple conditions (say Republican or Democratic), we can use the isin operator to simplify our code."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 31,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "Year\n",
       "1980     True\n",
       "1980     True\n",
       "1980    False\n",
       "1984     True\n",
       "1984     True\n",
       "1988     True\n",
       "1988     True\n",
       "1992     True\n",
       "1992     True\n",
       "1992    False\n",
       "1996     True\n",
       "1996     True\n",
       "1996    False\n",
       "2000     True\n",
       "2000     True\n",
       "2004     True\n",
       "2004     True\n",
       "2008     True\n",
       "2008     True\n",
       "2012     True\n",
       "2012     True\n",
       "2016     True\n",
       "2016     True\n",
       "Name: Party, dtype: bool"
      ]
     },
     "execution_count": 31,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "elections_year_index['Party'].isin([\"Republican\", \"Democratic\"])"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 32,
   "metadata": {},
   "outputs": [
    {
     "data": {
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       "  <tbody>\n",
       "    <tr>\n",
       "      <th>1980</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "      <td>50.7</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1980</th>\n",
       "      <td>Carter</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>41.0</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1984</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "      <td>58.8</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1984</th>\n",
       "      <td>Mondale</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>37.6</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1988</th>\n",
       "      <td>Bush</td>\n",
       "      <td>Republican</td>\n",
       "      <td>53.4</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1988</th>\n",
       "      <td>Dukakis</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>45.6</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1992</th>\n",
       "      <td>Clinton</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>43.0</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1992</th>\n",
       "      <td>Bush</td>\n",
       "      <td>Republican</td>\n",
       "      <td>37.4</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1996</th>\n",
       "      <td>Clinton</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>49.2</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1996</th>\n",
       "      <td>Dole</td>\n",
       "      <td>Republican</td>\n",
       "      <td>40.7</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2000</th>\n",
       "      <td>Gore</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>48.4</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2000</th>\n",
       "      <td>Bush</td>\n",
       "      <td>Republican</td>\n",
       "      <td>47.9</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2004</th>\n",
       "      <td>Kerry</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>48.3</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2004</th>\n",
       "      <td>Bush</td>\n",
       "      <td>Republican</td>\n",
       "      <td>50.7</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2008</th>\n",
       "      <td>Obama</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>52.9</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2008</th>\n",
       "      <td>McCain</td>\n",
       "      <td>Republican</td>\n",
       "      <td>45.7</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2012</th>\n",
       "      <td>Obama</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>51.1</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2012</th>\n",
       "      <td>Romney</td>\n",
       "      <td>Republican</td>\n",
       "      <td>47.2</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2016</th>\n",
       "      <td>Clinton</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>48.2</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2016</th>\n",
       "      <td>Trump</td>\n",
       "      <td>Republican</td>\n",
       "      <td>46.1</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "  </tbody>\n",
       "</table>\n",
       "</div>"
      ],
      "text/plain": [
       "     Candidate       Party     % Result\n",
       "Year                                   \n",
       "1980    Reagan  Republican  50.7    win\n",
       "1980    Carter  Democratic  41.0   loss\n",
       "1984    Reagan  Republican  58.8    win\n",
       "1984   Mondale  Democratic  37.6   loss\n",
       "1988      Bush  Republican  53.4    win\n",
       "1988   Dukakis  Democratic  45.6   loss\n",
       "1992   Clinton  Democratic  43.0    win\n",
       "1992      Bush  Republican  37.4   loss\n",
       "1996   Clinton  Democratic  49.2    win\n",
       "1996      Dole  Republican  40.7   loss\n",
       "2000      Gore  Democratic  48.4   loss\n",
       "2000      Bush  Republican  47.9    win\n",
       "2004     Kerry  Democratic  48.3   loss\n",
       "2004      Bush  Republican  50.7    win\n",
       "2008     Obama  Democratic  52.9    win\n",
       "2008    McCain  Republican  45.7   loss\n",
       "2012     Obama  Democratic  51.1    win\n",
       "2012    Romney  Republican  47.2   loss\n",
       "2016   Clinton  Democratic  48.2   loss\n",
       "2016     Trump  Republican  46.1    win"
      ]
     },
     "execution_count": 32,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "elections_year_index[elections_year_index['Party'].isin([\"Republican\", \"Democratic\"])]"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "An alternate simpler way to get back a specific set of rows is to use the `query` command."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 33,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "\u001b[1;31mSignature:\u001b[0m \u001b[0melections_year_index\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0mquery\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0mexpr\u001b[0m\u001b[1;33m,\u001b[0m \u001b[0minplace\u001b[0m\u001b[1;33m=\u001b[0m\u001b[1;32mFalse\u001b[0m\u001b[1;33m,\u001b[0m \u001b[1;33m**\u001b[0m\u001b[0mkwargs\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n",
       "\u001b[1;31mDocstring:\u001b[0m\n",
       "Query the columns of a DataFrame with a boolean expression.\n",
       "\n",
       "Parameters\n",
       "----------\n",
       "expr : str\n",
       "    The query string to evaluate.\n",
       "\n",
       "    You can refer to variables\n",
       "    in the environment by prefixing them with an '@' character like\n",
       "    ``@a + b``.\n",
       "\n",
       "    You can refer to column names that are not valid Python variable names\n",
       "    by surrounding them in backticks. Thus, column names containing spaces\n",
       "    or punctuations (besides underscores) or starting with digits must be\n",
       "    surrounded by backticks. (For example, a column named \"Area (cm^2) would\n",
       "    be referenced as `Area (cm^2)`). Column names which are Python keywords\n",
       "    (like \"list\", \"for\", \"import\", etc) cannot be used.\n",
       "\n",
       "    For example, if one of your columns is called ``a a`` and you want\n",
       "    to sum it with ``b``, your query should be ```a a` + b``.\n",
       "\n",
       "    .. versionadded:: 0.25.0\n",
       "        Backtick quoting introduced.\n",
       "\n",
       "    .. versionadded:: 1.0.0\n",
       "        Expanding functionality of backtick quoting for more than only spaces.\n",
       "\n",
       "inplace : bool\n",
       "    Whether the query should modify the data in place or return\n",
       "    a modified copy.\n",
       "**kwargs\n",
       "    See the documentation for :func:`eval` for complete details\n",
       "    on the keyword arguments accepted by :meth:`DataFrame.query`.\n",
       "\n",
       "Returns\n",
       "-------\n",
       "DataFrame or None\n",
       "    DataFrame resulting from the provided query expression or\n",
       "    None if ``inplace=True``.\n",
       "\n",
       "See Also\n",
       "--------\n",
       "eval : Evaluate a string describing operations on\n",
       "    DataFrame columns.\n",
       "DataFrame.eval : Evaluate a string describing operations on\n",
       "    DataFrame columns.\n",
       "\n",
       "Notes\n",
       "-----\n",
       "The result of the evaluation of this expression is first passed to\n",
       ":attr:`DataFrame.loc` and if that fails because of a\n",
       "multidimensional key (e.g., a DataFrame) then the result will be passed\n",
       "to :meth:`DataFrame.__getitem__`.\n",
       "\n",
       "This method uses the top-level :func:`eval` function to\n",
       "evaluate the passed query.\n",
       "\n",
       "The :meth:`~pandas.DataFrame.query` method uses a slightly\n",
       "modified Python syntax by default. For example, the ``&`` and ``|``\n",
       "(bitwise) operators have the precedence of their boolean cousins,\n",
       ":keyword:`and` and :keyword:`or`. This *is* syntactically valid Python,\n",
       "however the semantics are different.\n",
       "\n",
       "You can change the semantics of the expression by passing the keyword\n",
       "argument ``parser='python'``. This enforces the same semantics as\n",
       "evaluation in Python space. Likewise, you can pass ``engine='python'``\n",
       "to evaluate an expression using Python itself as a backend. This is not\n",
       "recommended as it is inefficient compared to using ``numexpr`` as the\n",
       "engine.\n",
       "\n",
       "The :attr:`DataFrame.index` and\n",
       ":attr:`DataFrame.columns` attributes of the\n",
       ":class:`~pandas.DataFrame` instance are placed in the query namespace\n",
       "by default, which allows you to treat both the index and columns of the\n",
       "frame as a column in the frame.\n",
       "The identifier ``index`` is used for the frame index; you can also\n",
       "use the name of the index to identify it in a query. Please note that\n",
       "Python keywords may not be used as identifiers.\n",
       "\n",
       "For further details and examples see the ``query`` documentation in\n",
       ":ref:`indexing <indexing.query>`.\n",
       "\n",
       "*Backtick quoted variables*\n",
       "\n",
       "Backtick quoted variables are parsed as literal Python code and\n",
       "are converted internally to a Python valid identifier.\n",
       "This can lead to the following problems.\n",
       "\n",
       "During parsing a number of disallowed characters inside the backtick\n",
       "quoted string are replaced by strings that are allowed as a Python identifier.\n",
       "These characters include all operators in Python, the space character, the\n",
       "question mark, the exclamation mark, the dollar sign, and the euro sign.\n",
       "For other characters that fall outside the ASCII range (U+0001..U+007F)\n",
       "and those that are not further specified in PEP 3131,\n",
       "the query parser will raise an error.\n",
       "This excludes whitespace different than the space character,\n",
       "but also the hashtag (as it is used for comments) and the backtick\n",
       "itself (backtick can also not be escaped).\n",
       "\n",
       "In a special case, quotes that make a pair around a backtick can\n",
       "confuse the parser.\n",
       "For example, ```it's` > `that's``` will raise an error,\n",
       "as it forms a quoted string (``'s > `that'``) with a backtick inside.\n",
       "\n",
       "See also the Python documentation about lexical analysis\n",
       "(https://docs.python.org/3/reference/lexical_analysis.html)\n",
       "in combination with the source code in :mod:`pandas.core.computation.parsing`.\n",
       "\n",
       "Examples\n",
       "--------\n",
       ">>> df = pd.DataFrame({'A': range(1, 6),\n",
       "...                    'B': range(10, 0, -2),\n",
       "...                    'C C': range(10, 5, -1)})\n",
       ">>> df\n",
       "   A   B  C C\n",
       "0  1  10   10\n",
       "1  2   8    9\n",
       "2  3   6    8\n",
       "3  4   4    7\n",
       "4  5   2    6\n",
       ">>> df.query('A > B')\n",
       "   A  B  C C\n",
       "4  5  2    6\n",
       "\n",
       "The previous expression is equivalent to\n",
       "\n",
       ">>> df[df.A > df.B]\n",
       "   A  B  C C\n",
       "4  5  2    6\n",
       "\n",
       "For columns with spaces in their name, you can use backtick quoting.\n",
       "\n",
       ">>> df.query('B == `C C`')\n",
       "   A   B  C C\n",
       "0  1  10   10\n",
       "\n",
       "The previous expression is equivalent to\n",
       "\n",
       ">>> df[df.B == df['C C']]\n",
       "   A   B  C C\n",
       "0  1  10   10\n",
       "\u001b[1;31mFile:\u001b[0m      c:\\users\\lkk\\documents\\developer\\.venv\\lib\\site-packages\\pandas\\core\\frame.py\n",
       "\u001b[1;31mType:\u001b[0m      method\n"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "elections_year_index.query?"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 34,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div>\n",
       "<style scoped>\n",
       "    .dataframe tbody tr th:only-of-type {\n",
       "        vertical-align: middle;\n",
       "    }\n",
       "\n",
       "    .dataframe tbody tr th {\n",
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       "    }\n",
       "\n",
       "    .dataframe thead th {\n",
       "        text-align: right;\n",
       "    }\n",
       "</style>\n",
       "<table border=\"1\" class=\"dataframe\">\n",
       "  <thead>\n",
       "    <tr style=\"text-align: right;\">\n",
       "      <th></th>\n",
       "      <th>Candidate</th>\n",
       "      <th>Party</th>\n",
       "      <th>%</th>\n",
       "      <th>Result</th>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>Year</th>\n",
       "      <th></th>\n",
       "      <th></th>\n",
       "      <th></th>\n",
       "      <th></th>\n",
       "    </tr>\n",
       "  </thead>\n",
       "  <tbody>\n",
       "    <tr>\n",
       "      <th>1980</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "      <td>50.7</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1984</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "      <td>58.8</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1988</th>\n",
       "      <td>Bush</td>\n",
       "      <td>Republican</td>\n",
       "      <td>53.4</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1992</th>\n",
       "      <td>Clinton</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>43.0</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1996</th>\n",
       "      <td>Clinton</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>49.2</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "  </tbody>\n",
       "</table>\n",
       "</div>"
      ],
      "text/plain": [
       "     Candidate       Party     % Result\n",
       "Year                                   \n",
       "1980    Reagan  Republican  50.7    win\n",
       "1984    Reagan  Republican  58.8    win\n",
       "1988      Bush  Republican  53.4    win\n",
       "1992   Clinton  Democratic  43.0    win\n",
       "1996   Clinton  Democratic  49.2    win"
      ]
     },
     "execution_count": 34,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "elections_year_index.query(\"Result == 'win' and Year < 2000\")"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Label-based access with `loc`"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 35,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div>\n",
       "<style scoped>\n",
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       "\n",
       "    .dataframe tbody tr th {\n",
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       "    }\n",
       "\n",
       "    .dataframe thead th {\n",
       "        text-align: right;\n",
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       "</style>\n",
       "<table border=\"1\" class=\"dataframe\">\n",
       "  <thead>\n",
       "    <tr style=\"text-align: right;\">\n",
       "      <th></th>\n",
       "      <th>Candidate</th>\n",
       "      <th>Party</th>\n",
       "      <th>%</th>\n",
       "      <th>Year</th>\n",
       "      <th>Result</th>\n",
       "    </tr>\n",
       "  </thead>\n",
       "  <tbody>\n",
       "    <tr>\n",
       "      <th>0</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "      <td>50.7</td>\n",
       "      <td>1980</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1</th>\n",
       "      <td>Carter</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>41.0</td>\n",
       "      <td>1980</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2</th>\n",
       "      <td>Anderson</td>\n",
       "      <td>Independent</td>\n",
       "      <td>6.6</td>\n",
       "      <td>1980</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>3</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "      <td>58.8</td>\n",
       "      <td>1984</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>4</th>\n",
       "      <td>Mondale</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>37.6</td>\n",
       "      <td>1984</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "  </tbody>\n",
       "</table>\n",
       "</div>"
      ],
      "text/plain": [
       "  Candidate        Party     %  Year Result\n",
       "0    Reagan   Republican  50.7  1980    win\n",
       "1    Carter   Democratic  41.0  1980   loss\n",
       "2  Anderson  Independent   6.6  1980   loss\n",
       "3    Reagan   Republican  58.8  1984    win\n",
       "4   Mondale   Democratic  37.6  1984   loss"
      ]
     },
     "execution_count": 35,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "elections.head(5)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 36,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div>\n",
       "<style scoped>\n",
       "    .dataframe tbody tr th:only-of-type {\n",
       "        vertical-align: middle;\n",
       "    }\n",
       "\n",
       "    .dataframe tbody tr th {\n",
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       "    }\n",
       "\n",
       "    .dataframe thead th {\n",
       "        text-align: right;\n",
       "    }\n",
       "</style>\n",
       "<table border=\"1\" class=\"dataframe\">\n",
       "  <thead>\n",
       "    <tr style=\"text-align: right;\">\n",
       "      <th></th>\n",
       "      <th>Candidate</th>\n",
       "      <th>Party</th>\n",
       "      <th>Year</th>\n",
       "    </tr>\n",
       "  </thead>\n",
       "  <tbody>\n",
       "    <tr>\n",
       "      <th>0</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "      <td>1980</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1</th>\n",
       "      <td>Carter</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>1980</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2</th>\n",
       "      <td>Anderson</td>\n",
       "      <td>Independent</td>\n",
       "      <td>1980</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>3</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "      <td>1984</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>4</th>\n",
       "      <td>Mondale</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>1984</td>\n",
       "    </tr>\n",
       "  </tbody>\n",
       "</table>\n",
       "</div>"
      ],
      "text/plain": [
       "  Candidate        Party  Year\n",
       "0    Reagan   Republican  1980\n",
       "1    Carter   Democratic  1980\n",
       "2  Anderson  Independent  1980\n",
       "3    Reagan   Republican  1984\n",
       "4   Mondale   Democratic  1984"
      ]
     },
     "execution_count": 36,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "elections.loc[[0, 1, 2, 3, 4], ['Candidate','Party', 'Year']]"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Note: The `loc` command won't work with numeric arguments if we're using the elections DataFrame that was indexed by year."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 37,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div>\n",
       "<style scoped>\n",
       "    .dataframe tbody tr th:only-of-type {\n",
       "        vertical-align: middle;\n",
       "    }\n",
       "\n",
       "    .dataframe tbody tr th {\n",
       "        vertical-align: top;\n",
       "    }\n",
       "\n",
       "    .dataframe thead th {\n",
       "        text-align: right;\n",
       "    }\n",
       "</style>\n",
       "<table border=\"1\" class=\"dataframe\">\n",
       "  <thead>\n",
       "    <tr style=\"text-align: right;\">\n",
       "      <th></th>\n",
       "      <th>Candidate</th>\n",
       "      <th>Party</th>\n",
       "      <th>%</th>\n",
       "      <th>Result</th>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>Year</th>\n",
       "      <th></th>\n",
       "      <th></th>\n",
       "      <th></th>\n",
       "      <th></th>\n",
       "    </tr>\n",
       "  </thead>\n",
       "  <tbody>\n",
       "    <tr>\n",
       "      <th>1980</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "      <td>50.7</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1980</th>\n",
       "      <td>Carter</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>41.0</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1980</th>\n",
       "      <td>Anderson</td>\n",
       "      <td>Independent</td>\n",
       "      <td>6.6</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1984</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "      <td>58.8</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1984</th>\n",
       "      <td>Mondale</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>37.6</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "  </tbody>\n",
       "</table>\n",
       "</div>"
      ],
      "text/plain": [
       "     Candidate        Party     % Result\n",
       "Year                                    \n",
       "1980    Reagan   Republican  50.7    win\n",
       "1980    Carter   Democratic  41.0   loss\n",
       "1980  Anderson  Independent   6.6   loss\n",
       "1984    Reagan   Republican  58.8    win\n",
       "1984   Mondale   Democratic  37.6   loss"
      ]
     },
     "execution_count": 37,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "elections_year_index.head(5)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 38,
   "metadata": {},
   "outputs": [
    {
     "ename": "KeyError",
     "evalue": "\"None of [Int64Index([0, 1, 2, 3, 4], dtype='int64', name='Year')] are in the [index]\"",
     "output_type": "error",
     "traceback": [
      "\u001b[1;31m---------------------------------------------------------------------------\u001b[0m",
      "\u001b[1;31mKeyError\u001b[0m                                  Traceback (most recent call last)",
      "\u001b[1;32m<ipython-input-38-216dbccfb42e>\u001b[0m in \u001b[0;36m<module>\u001b[1;34m\u001b[0m\n\u001b[0;32m      1\u001b[0m \u001b[1;31m#causes error\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[1;32m----> 2\u001b[1;33m \u001b[0melections_year_index\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0mloc\u001b[0m\u001b[1;33m[\u001b[0m\u001b[1;33m[\u001b[0m\u001b[1;36m0\u001b[0m\u001b[1;33m,\u001b[0m \u001b[1;36m1\u001b[0m\u001b[1;33m,\u001b[0m \u001b[1;36m2\u001b[0m\u001b[1;33m,\u001b[0m \u001b[1;36m3\u001b[0m\u001b[1;33m,\u001b[0m \u001b[1;36m4\u001b[0m\u001b[1;33m]\u001b[0m\u001b[1;33m,\u001b[0m \u001b[1;33m[\u001b[0m\u001b[1;34m'Candidate'\u001b[0m\u001b[1;33m,\u001b[0m\u001b[1;34m'Party'\u001b[0m\u001b[1;33m]\u001b[0m\u001b[1;33m]\u001b[0m\u001b[1;31m#\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0m",
      "\u001b[1;32mc:\\users\\lkk\\documents\\developer\\.venv\\lib\\site-packages\\pandas\\core\\indexing.py\u001b[0m in \u001b[0;36m__getitem__\u001b[1;34m(self, key)\u001b[0m\n\u001b[0;32m    887\u001b[0m                     \u001b[1;31m# AttributeError for IntervalTree get_value\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0;32m    888\u001b[0m                     \u001b[1;32mreturn\u001b[0m \u001b[0mself\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0mobj\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0m_get_value\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;33m*\u001b[0m\u001b[0mkey\u001b[0m\u001b[1;33m,\u001b[0m \u001b[0mtakeable\u001b[0m\u001b[1;33m=\u001b[0m\u001b[0mself\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0m_takeable\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[1;32m--> 889\u001b[1;33m             \u001b[1;32mreturn\u001b[0m \u001b[0mself\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0m_getitem_tuple\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0mkey\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0m\u001b[0;32m    890\u001b[0m         \u001b[1;32melse\u001b[0m\u001b[1;33m:\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0;32m    891\u001b[0m             \u001b[1;31m# we by definition only have the 0th axis\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n",
      "\u001b[1;32mc:\\users\\lkk\\documents\\developer\\.venv\\lib\\site-packages\\pandas\\core\\indexing.py\u001b[0m in \u001b[0;36m_getitem_tuple\u001b[1;34m(self, tup)\u001b[0m\n\u001b[0;32m   1065\u001b[0m         \u001b[1;31m# ugly hack for GH #836\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0;32m   1066\u001b[0m         \u001b[1;32mif\u001b[0m \u001b[0mself\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0m_multi_take_opportunity\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0mtup\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m:\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[1;32m-> 1067\u001b[1;33m             \u001b[1;32mreturn\u001b[0m \u001b[0mself\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0m_multi_take\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0mtup\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0m\u001b[0;32m   1068\u001b[0m \u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0;32m   1069\u001b[0m         \u001b[1;32mreturn\u001b[0m \u001b[0mself\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0m_getitem_tuple_same_dim\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0mtup\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n",
      "\u001b[1;32mc:\\users\\lkk\\documents\\developer\\.venv\\lib\\site-packages\\pandas\\core\\indexing.py\u001b[0m in \u001b[0;36m_multi_take\u001b[1;34m(self, tup)\u001b[0m\n\u001b[0;32m   1017\u001b[0m         \"\"\"\n\u001b[0;32m   1018\u001b[0m         \u001b[1;31m# GH 836\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[1;32m-> 1019\u001b[1;33m         d = {\n\u001b[0m\u001b[0;32m   1020\u001b[0m             \u001b[0maxis\u001b[0m\u001b[1;33m:\u001b[0m \u001b[0mself\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0m_get_listlike_indexer\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0mkey\u001b[0m\u001b[1;33m,\u001b[0m \u001b[0maxis\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0;32m   1021\u001b[0m             \u001b[1;32mfor\u001b[0m \u001b[1;33m(\u001b[0m\u001b[0mkey\u001b[0m\u001b[1;33m,\u001b[0m \u001b[0maxis\u001b[0m\u001b[1;33m)\u001b[0m \u001b[1;32min\u001b[0m \u001b[0mzip\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0mtup\u001b[0m\u001b[1;33m,\u001b[0m \u001b[0mself\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0mobj\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0m_AXIS_ORDERS\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n",
      "\u001b[1;32mc:\\users\\lkk\\documents\\developer\\.venv\\lib\\site-packages\\pandas\\core\\indexing.py\u001b[0m in \u001b[0;36m<dictcomp>\u001b[1;34m(.0)\u001b[0m\n\u001b[0;32m   1018\u001b[0m         \u001b[1;31m# GH 836\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0;32m   1019\u001b[0m         d = {\n\u001b[1;32m-> 1020\u001b[1;33m             \u001b[0maxis\u001b[0m\u001b[1;33m:\u001b[0m \u001b[0mself\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0m_get_listlike_indexer\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0mkey\u001b[0m\u001b[1;33m,\u001b[0m \u001b[0maxis\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0m\u001b[0;32m   1021\u001b[0m             \u001b[1;32mfor\u001b[0m \u001b[1;33m(\u001b[0m\u001b[0mkey\u001b[0m\u001b[1;33m,\u001b[0m \u001b[0maxis\u001b[0m\u001b[1;33m)\u001b[0m \u001b[1;32min\u001b[0m \u001b[0mzip\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0mtup\u001b[0m\u001b[1;33m,\u001b[0m \u001b[0mself\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0mobj\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0m_AXIS_ORDERS\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0;32m   1022\u001b[0m         }\n",
      "\u001b[1;32mc:\\users\\lkk\\documents\\developer\\.venv\\lib\\site-packages\\pandas\\core\\indexing.py\u001b[0m in \u001b[0;36m_get_listlike_indexer\u001b[1;34m(self, key, axis, raise_missing)\u001b[0m\n\u001b[0;32m   1264\u001b[0m             \u001b[0mkeyarr\u001b[0m\u001b[1;33m,\u001b[0m \u001b[0mindexer\u001b[0m\u001b[1;33m,\u001b[0m \u001b[0mnew_indexer\u001b[0m \u001b[1;33m=\u001b[0m \u001b[0max\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0m_reindex_non_unique\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0mkeyarr\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0;32m   1265\u001b[0m \u001b[1;33m\u001b[0m\u001b[0m\n\u001b[1;32m-> 1266\u001b[1;33m         \u001b[0mself\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0m_validate_read_indexer\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0mkeyarr\u001b[0m\u001b[1;33m,\u001b[0m \u001b[0mindexer\u001b[0m\u001b[1;33m,\u001b[0m \u001b[0maxis\u001b[0m\u001b[1;33m,\u001b[0m \u001b[0mraise_missing\u001b[0m\u001b[1;33m=\u001b[0m\u001b[0mraise_missing\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0m\u001b[0;32m   1267\u001b[0m         \u001b[1;32mreturn\u001b[0m \u001b[0mkeyarr\u001b[0m\u001b[1;33m,\u001b[0m \u001b[0mindexer\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0;32m   1268\u001b[0m \u001b[1;33m\u001b[0m\u001b[0m\n",
      "\u001b[1;32mc:\\users\\lkk\\documents\\developer\\.venv\\lib\\site-packages\\pandas\\core\\indexing.py\u001b[0m in \u001b[0;36m_validate_read_indexer\u001b[1;34m(self, key, indexer, axis, raise_missing)\u001b[0m\n\u001b[0;32m   1306\u001b[0m             \u001b[1;32mif\u001b[0m \u001b[0mmissing\u001b[0m \u001b[1;33m==\u001b[0m \u001b[0mlen\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0mindexer\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m:\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0;32m   1307\u001b[0m                 \u001b[0maxis_name\u001b[0m \u001b[1;33m=\u001b[0m \u001b[0mself\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0mobj\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0m_get_axis_name\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0maxis\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[1;32m-> 1308\u001b[1;33m                 \u001b[1;32mraise\u001b[0m \u001b[0mKeyError\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;34mf\"None of [{key}] are in the [{axis_name}]\"\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0m\u001b[0;32m   1309\u001b[0m \u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0;32m   1310\u001b[0m             \u001b[0max\u001b[0m \u001b[1;33m=\u001b[0m \u001b[0mself\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0mobj\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0m_get_axis\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0maxis\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n",
      "\u001b[1;31mKeyError\u001b[0m: \"None of [Int64Index([0, 1, 2, 3, 4], dtype='int64', name='Year')] are in the [index]\""
     ]
    }
   ],
   "source": [
    "#causes error\n",
    "elections_year_index.loc[[0, 1, 2, 3, 4], ['Candidate','Party']]#"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 39,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div>\n",
       "<style scoped>\n",
       "    .dataframe tbody tr th:only-of-type {\n",
       "        vertical-align: middle;\n",
       "    }\n",
       "\n",
       "    .dataframe tbody tr th {\n",
       "        vertical-align: top;\n",
       "    }\n",
       "\n",
       "    .dataframe thead th {\n",
       "        text-align: right;\n",
       "    }\n",
       "</style>\n",
       "<table border=\"1\" class=\"dataframe\">\n",
       "  <thead>\n",
       "    <tr style=\"text-align: right;\">\n",
       "      <th></th>\n",
       "      <th>Candidate</th>\n",
       "      <th>Party</th>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>Year</th>\n",
       "      <th></th>\n",
       "      <th></th>\n",
       "    </tr>\n",
       "  </thead>\n",
       "  <tbody>\n",
       "    <tr>\n",
       "      <th>1980</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1980</th>\n",
       "      <td>Carter</td>\n",
       "      <td>Democratic</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1980</th>\n",
       "      <td>Anderson</td>\n",
       "      <td>Independent</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1984</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1984</th>\n",
       "      <td>Mondale</td>\n",
       "      <td>Democratic</td>\n",
       "    </tr>\n",
       "  </tbody>\n",
       "</table>\n",
       "</div>"
      ],
      "text/plain": [
       "     Candidate        Party\n",
       "Year                       \n",
       "1980    Reagan   Republican\n",
       "1980    Carter   Democratic\n",
       "1980  Anderson  Independent\n",
       "1984    Reagan   Republican\n",
       "1984   Mondale   Democratic"
      ]
     },
     "execution_count": 39,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "elections_year_index.loc[[1980, 1984], ['Candidate','Party']]"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Loc also supports slicing (for all types, including numeric and string labels!). Note that the slicing for loc is **inclusive**, even for numeric slices."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 40,
   "metadata": {
    "scrolled": true
   },
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div>\n",
       "<style scoped>\n",
       "    .dataframe tbody tr th:only-of-type {\n",
       "        vertical-align: middle;\n",
       "    }\n",
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       "    <tr style=\"text-align: right;\">\n",
       "      <th></th>\n",
       "      <th>Candidate</th>\n",
       "      <th>Party</th>\n",
       "      <th>%</th>\n",
       "      <th>Year</th>\n",
       "    </tr>\n",
       "  </thead>\n",
       "  <tbody>\n",
       "    <tr>\n",
       "      <th>0</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "      <td>50.7</td>\n",
       "      <td>1980</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1</th>\n",
       "      <td>Carter</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>41.0</td>\n",
       "      <td>1980</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2</th>\n",
       "      <td>Anderson</td>\n",
       "      <td>Independent</td>\n",
       "      <td>6.6</td>\n",
       "      <td>1980</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>3</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "      <td>58.8</td>\n",
       "      <td>1984</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>4</th>\n",
       "      <td>Mondale</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>37.6</td>\n",
       "      <td>1984</td>\n",
       "    </tr>\n",
       "  </tbody>\n",
       "</table>\n",
       "</div>"
      ],
      "text/plain": [
       "  Candidate        Party     %  Year\n",
       "0    Reagan   Republican  50.7  1980\n",
       "1    Carter   Democratic  41.0  1980\n",
       "2  Anderson  Independent   6.6  1980\n",
       "3    Reagan   Republican  58.8  1984\n",
       "4   Mondale   Democratic  37.6  1984"
      ]
     },
     "execution_count": 40,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "elections.loc[0:4, 'Candidate':'Year']"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 41,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
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       "      <th>Party</th>\n",
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       "    <tr>\n",
       "      <th>Year</th>\n",
       "      <th></th>\n",
       "      <th></th>\n",
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       "  <tbody>\n",
       "    <tr>\n",
       "      <th>1980</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1980</th>\n",
       "      <td>Carter</td>\n",
       "      <td>Democratic</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1980</th>\n",
       "      <td>Anderson</td>\n",
       "      <td>Independent</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1984</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1984</th>\n",
       "      <td>Mondale</td>\n",
       "      <td>Democratic</td>\n",
       "    </tr>\n",
       "  </tbody>\n",
       "</table>\n",
       "</div>"
      ],
      "text/plain": [
       "     Candidate        Party\n",
       "Year                       \n",
       "1980    Reagan   Republican\n",
       "1980    Carter   Democratic\n",
       "1980  Anderson  Independent\n",
       "1984    Reagan   Republican\n",
       "1984   Mondale   Democratic"
      ]
     },
     "execution_count": 41,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "elections_year_index.loc[1980:1984, 'Candidate':'Party']"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "If we provide only a single label for the column argument, we get back a Series."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 42,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "0      Reagan\n",
       "1      Carter\n",
       "2    Anderson\n",
       "3      Reagan\n",
       "4     Mondale\n",
       "Name: Candidate, dtype: object"
      ]
     },
     "execution_count": 42,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "elections.loc[0:4, 'Candidate']"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "If we want a data frame instead and don't want to use to_frame, we can provde a list containing the column name."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 43,
   "metadata": {
    "scrolled": true
   },
   "outputs": [
    {
     "data": {
      "text/html": [
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       "  </thead>\n",
       "  <tbody>\n",
       "    <tr>\n",
       "      <th>0</th>\n",
       "      <td>Reagan</td>\n",
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       "    <tr>\n",
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       "      <td>Carter</td>\n",
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       "      <td>Mondale</td>\n",
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      ],
      "text/plain": [
       "  Candidate\n",
       "0    Reagan\n",
       "1    Carter\n",
       "2  Anderson\n",
       "3    Reagan\n",
       "4   Mondale"
      ]
     },
     "execution_count": 43,
     "metadata": {},
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   "source": [
    "elections.loc[0:4, ['Candidate']]"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "If we give only one row but many column labels, we'll get back a Series corresponding to a row of the table. This new Series has a neat index, where each entry is the name of the column that the data came from."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 44,
   "metadata": {},
   "outputs": [
    {
     "data": {
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       "      <th></th>\n",
       "      <th>Candidate</th>\n",
       "      <th>Party</th>\n",
       "      <th>%</th>\n",
       "      <th>Year</th>\n",
       "      <th>Result</th>\n",
       "    </tr>\n",
       "  </thead>\n",
       "  <tbody>\n",
       "    <tr>\n",
       "      <th>0</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "      <td>50.7</td>\n",
       "      <td>1980</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "  </tbody>\n",
       "</table>\n",
       "</div>"
      ],
      "text/plain": [
       "  Candidate       Party     %  Year Result\n",
       "0    Reagan  Republican  50.7  1980    win"
      ]
     },
     "execution_count": 44,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "elections.head(1)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 45,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "Candidate        Reagan\n",
       "Party        Republican\n",
       "%                  50.7\n",
       "Year               1980\n",
       "Name: 0, dtype: object"
      ]
     },
     "execution_count": 45,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "elections.loc[0, 'Candidate':'Year']"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 46,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
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       "      <th>0</th>\n",
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      "text/plain": [
       "  Candidate       Party     %  Year\n",
       "0    Reagan  Republican  50.7  1980"
      ]
     },
     "execution_count": 46,
     "metadata": {},
     "output_type": "execute_result"
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   "source": [
    "elections.loc[[0], 'Candidate':'Year']"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "If we omit the column argument altogether, the default behavior is to retrieve all columns. "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 47,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
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       "    </tr>\n",
       "  </thead>\n",
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       "      <th>2</th>\n",
       "      <td>Anderson</td>\n",
       "      <td>Independent</td>\n",
       "      <td>6.6</td>\n",
       "      <td>1980</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>4</th>\n",
       "      <td>Mondale</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>37.6</td>\n",
       "      <td>1984</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>5</th>\n",
       "      <td>Bush</td>\n",
       "      <td>Republican</td>\n",
       "      <td>53.4</td>\n",
       "      <td>1988</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "  </tbody>\n",
       "</table>\n",
       "</div>"
      ],
      "text/plain": [
       "  Candidate        Party     %  Year Result\n",
       "2  Anderson  Independent   6.6  1980   loss\n",
       "4   Mondale   Democratic  37.6  1984   loss\n",
       "5      Bush   Republican  53.4  1988    win"
      ]
     },
     "execution_count": 47,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "elections.loc[[2, 4, 5]]"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Loc also supports boolean array inputs instead of labels. The Boolean arrays _must_ be of the same length as the row/column shape of the dataframe, respectively (in versions prior to 0.25, Pandas used to allow size mismatches and would assume the missing values were all False, [this was changed in 2019](https://github.com/pandas-dev/pandas/pull/26911))."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 48,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div>\n",
       "<style scoped>\n",
       "    .dataframe tbody tr th:only-of-type {\n",
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       "    </tr>\n",
       "  </thead>\n",
       "  <tbody>\n",
       "    <tr>\n",
       "      <th>0</th>\n",
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       "    <tr>\n",
       "      <th>3</th>\n",
       "      <td>Reagan</td>\n",
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       "    <tr>\n",
       "      <th>6</th>\n",
       "      <td>Dukakis</td>\n",
       "      <td>1988</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>7</th>\n",
       "      <td>Clinton</td>\n",
       "      <td>1992</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>8</th>\n",
       "      <td>Bush</td>\n",
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       "    <tr>\n",
       "      <th>11</th>\n",
       "      <td>Dole</td>\n",
       "      <td>1996</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>12</th>\n",
       "      <td>Perot</td>\n",
       "      <td>1996</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>13</th>\n",
       "      <td>Gore</td>\n",
       "      <td>2000</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>15</th>\n",
       "      <td>Kerry</td>\n",
       "      <td>2004</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>16</th>\n",
       "      <td>Bush</td>\n",
       "      <td>2004</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>20</th>\n",
       "      <td>Romney</td>\n",
       "      <td>2012</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "  </tbody>\n",
       "</table>\n",
       "</div>"
      ],
      "text/plain": [
       "   Candidate  Year Result\n",
       "0     Reagan  1980    win\n",
       "3     Reagan  1984    win\n",
       "6    Dukakis  1988   loss\n",
       "7    Clinton  1992    win\n",
       "8       Bush  1992   loss\n",
       "11      Dole  1996   loss\n",
       "12     Perot  1996   loss\n",
       "13      Gore  2000   loss\n",
       "15     Kerry  2004   loss\n",
       "16      Bush  2004    win\n",
       "20    Romney  2012   loss"
      ]
     },
     "execution_count": 48,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "elections.loc[[True, False, False, True, False, False, True, True, True, False, False, True, \n",
    "               True, True, False, True, True, False, False, False, True, False, False], # row mask\n",
    "              [True, False, False, True, True] # column mask\n",
    "             ]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 49,
   "metadata": {
    "scrolled": true
   },
   "outputs": [
    {
     "data": {
      "text/html": [
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       "      <th>Year</th>\n",
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       "  Candidate  Year\n",
       "0    Reagan  1980\n",
       "3    Reagan  1984"
      ]
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     "execution_count": 49,
     "metadata": {},
     "output_type": "execute_result"
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   ],
   "source": [
    "elections.loc[[0, 3], ['Candidate', 'Year']]"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "We can use boolean array arguments for one axis of the data, and labels for the other."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 50,
   "metadata": {},
   "outputs": [
    {
     "data": {
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       "    <tr>\n",
       "      <th>0</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "      <td>50.7</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>3</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "      <td>58.8</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>6</th>\n",
       "      <td>Dukakis</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>45.6</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>7</th>\n",
       "      <td>Clinton</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>43.0</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>8</th>\n",
       "      <td>Bush</td>\n",
       "      <td>Republican</td>\n",
       "      <td>37.4</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>11</th>\n",
       "      <td>Dole</td>\n",
       "      <td>Republican</td>\n",
       "      <td>40.7</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>12</th>\n",
       "      <td>Perot</td>\n",
       "      <td>Independent</td>\n",
       "      <td>8.4</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>13</th>\n",
       "      <td>Gore</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>48.4</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>15</th>\n",
       "      <td>Kerry</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>48.3</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>16</th>\n",
       "      <td>Bush</td>\n",
       "      <td>Republican</td>\n",
       "      <td>50.7</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>20</th>\n",
       "      <td>Romney</td>\n",
       "      <td>Republican</td>\n",
       "      <td>47.2</td>\n",
       "    </tr>\n",
       "  </tbody>\n",
       "</table>\n",
       "</div>"
      ],
      "text/plain": [
       "   Candidate        Party     %\n",
       "0     Reagan   Republican  50.7\n",
       "3     Reagan   Republican  58.8\n",
       "6    Dukakis   Democratic  45.6\n",
       "7    Clinton   Democratic  43.0\n",
       "8       Bush   Republican  37.4\n",
       "11      Dole   Republican  40.7\n",
       "12     Perot  Independent   8.4\n",
       "13      Gore   Democratic  48.4\n",
       "15     Kerry   Democratic  48.3\n",
       "16      Bush   Republican  50.7\n",
       "20    Romney   Republican  47.2"
      ]
     },
     "execution_count": 50,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "elections.loc[[True, False, False, True, False, False, True, True, True, False, False, True, \n",
    "               True, True, False, True, True, False, False, False, True, False, False], # row mask\n",
    "              \n",
    "              'Candidate':'%' # column label slice\n",
    "             ]"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "A student asks what happens if you give scalar arguments for the requested rows AND columns. The answer is that you get back just a single value."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 51,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "48.3"
      ]
     },
     "execution_count": 51,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "elections.loc[15, '%']"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Positional access with `iloc`"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "loc's cousin iloc is very similar, but is used to access based on numerical position instead of label. For example, to access to the top 3 rows and top 3 columns of a table, we can use [0:3, 0:3]. iloc slicing is **exclusive**, just like standard Python slicing of numerical values."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 52,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div>\n",
       "<style scoped>\n",
       "    .dataframe tbody tr th:only-of-type {\n",
       "        vertical-align: middle;\n",
       "    }\n",
       "\n",
       "    .dataframe tbody tr th {\n",
       "        vertical-align: top;\n",
       "    }\n",
       "\n",
       "    .dataframe thead th {\n",
       "        text-align: right;\n",
       "    }\n",
       "</style>\n",
       "<table border=\"1\" class=\"dataframe\">\n",
       "  <thead>\n",
       "    <tr style=\"text-align: right;\">\n",
       "      <th></th>\n",
       "      <th>Candidate</th>\n",
       "      <th>Party</th>\n",
       "      <th>%</th>\n",
       "      <th>Year</th>\n",
       "      <th>Result</th>\n",
       "    </tr>\n",
       "  </thead>\n",
       "  <tbody>\n",
       "    <tr>\n",
       "      <th>0</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "      <td>50.7</td>\n",
       "      <td>1980</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1</th>\n",
       "      <td>Carter</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>41.0</td>\n",
       "      <td>1980</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2</th>\n",
       "      <td>Anderson</td>\n",
       "      <td>Independent</td>\n",
       "      <td>6.6</td>\n",
       "      <td>1980</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>3</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "      <td>58.8</td>\n",
       "      <td>1984</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>4</th>\n",
       "      <td>Mondale</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>37.6</td>\n",
       "      <td>1984</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "  </tbody>\n",
       "</table>\n",
       "</div>"
      ],
      "text/plain": [
       "  Candidate        Party     %  Year Result\n",
       "0    Reagan   Republican  50.7  1980    win\n",
       "1    Carter   Democratic  41.0  1980   loss\n",
       "2  Anderson  Independent   6.6  1980   loss\n",
       "3    Reagan   Republican  58.8  1984    win\n",
       "4   Mondale   Democratic  37.6  1984   loss"
      ]
     },
     "execution_count": 52,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "elections.head(5)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 53,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div>\n",
       "<style scoped>\n",
       "    .dataframe tbody tr th:only-of-type {\n",
       "        vertical-align: middle;\n",
       "    }\n",
       "\n",
       "    .dataframe tbody tr th {\n",
       "        vertical-align: top;\n",
       "    }\n",
       "\n",
       "    .dataframe thead th {\n",
       "        text-align: right;\n",
       "    }\n",
       "</style>\n",
       "<table border=\"1\" class=\"dataframe\">\n",
       "  <thead>\n",
       "    <tr style=\"text-align: right;\">\n",
       "      <th></th>\n",
       "      <th>%</th>\n",
       "      <th>Year</th>\n",
       "      <th>Result</th>\n",
       "    </tr>\n",
       "  </thead>\n",
       "  <tbody>\n",
       "    <tr>\n",
       "      <th>0</th>\n",
       "      <td>50.7</td>\n",
       "      <td>1980</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1</th>\n",
       "      <td>41.0</td>\n",
       "      <td>1980</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2</th>\n",
       "      <td>6.6</td>\n",
       "      <td>1980</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "  </tbody>\n",
       "</table>\n",
       "</div>"
      ],
      "text/plain": [
       "      %  Year Result\n",
       "0  50.7  1980    win\n",
       "1  41.0  1980   loss\n",
       "2   6.6  1980   loss"
      ]
     },
     "execution_count": 53,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "elections.iloc[:3, 2:]"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "We will use both loc and iloc in the course. Loc is generally preferred for a number of reasons, for example: \n",
    "\n",
    "1. It is harder to make mistakes since you have to literally write out what you want to get.\n",
    "2. Code is easier to read, because the reader doesn't have to know e.g. what column #31 represents.\n",
    "3. It is robust against permutations of the data, e.g. the social security administration switches the order of two columns.\n",
    "\n",
    "However, iloc is sometimes more convenient. We'll provide examples of when iloc is the superior choice."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Sampling"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Pandas dataframes also make it easy to get a sample. We simply use the `sample` method and provide the number of samples that we'd like as the arugment. Sampling is done without replacement by default. Set `replace=True` if you want replacement."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 54,
   "metadata": {
    "scrolled": true
   },
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div>\n",
       "<style scoped>\n",
       "    .dataframe tbody tr th:only-of-type {\n",
       "        vertical-align: middle;\n",
       "    }\n",
       "\n",
       "    .dataframe tbody tr th {\n",
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       "    }\n",
       "\n",
       "    .dataframe thead th {\n",
       "        text-align: right;\n",
       "    }\n",
       "</style>\n",
       "<table border=\"1\" class=\"dataframe\">\n",
       "  <thead>\n",
       "    <tr style=\"text-align: right;\">\n",
       "      <th></th>\n",
       "      <th>Candidate</th>\n",
       "      <th>Party</th>\n",
       "      <th>%</th>\n",
       "      <th>Year</th>\n",
       "      <th>Result</th>\n",
       "    </tr>\n",
       "  </thead>\n",
       "  <tbody>\n",
       "    <tr>\n",
       "      <th>12</th>\n",
       "      <td>Perot</td>\n",
       "      <td>Independent</td>\n",
       "      <td>8.4</td>\n",
       "      <td>1996</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>7</th>\n",
       "      <td>Clinton</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>43.0</td>\n",
       "      <td>1992</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>16</th>\n",
       "      <td>Bush</td>\n",
       "      <td>Republican</td>\n",
       "      <td>50.7</td>\n",
       "      <td>2004</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>0</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "      <td>50.7</td>\n",
       "      <td>1980</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>10</th>\n",
       "      <td>Clinton</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>49.2</td>\n",
       "      <td>1996</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2</th>\n",
       "      <td>Anderson</td>\n",
       "      <td>Independent</td>\n",
       "      <td>6.6</td>\n",
       "      <td>1980</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>5</th>\n",
       "      <td>Bush</td>\n",
       "      <td>Republican</td>\n",
       "      <td>53.4</td>\n",
       "      <td>1988</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>14</th>\n",
       "      <td>Bush</td>\n",
       "      <td>Republican</td>\n",
       "      <td>47.9</td>\n",
       "      <td>2000</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1</th>\n",
       "      <td>Carter</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>41.0</td>\n",
       "      <td>1980</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>9</th>\n",
       "      <td>Perot</td>\n",
       "      <td>Independent</td>\n",
       "      <td>18.9</td>\n",
       "      <td>1992</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "  </tbody>\n",
       "</table>\n",
       "</div>"
      ],
      "text/plain": [
       "   Candidate        Party     %  Year Result\n",
       "12     Perot  Independent   8.4  1996   loss\n",
       "7    Clinton   Democratic  43.0  1992    win\n",
       "16      Bush   Republican  50.7  2004    win\n",
       "0     Reagan   Republican  50.7  1980    win\n",
       "10   Clinton   Democratic  49.2  1996    win\n",
       "2   Anderson  Independent   6.6  1980   loss\n",
       "5       Bush   Republican  53.4  1988    win\n",
       "14      Bush   Republican  47.9  2000    win\n",
       "1     Carter   Democratic  41.0  1980   loss\n",
       "9      Perot  Independent  18.9  1992   loss"
      ]
     },
     "execution_count": 54,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "elections.sample(10)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 55,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div>\n",
       "<style scoped>\n",
       "    .dataframe tbody tr th:only-of-type {\n",
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       "\n",
       "    .dataframe tbody tr th {\n",
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       "    }\n",
       "\n",
       "    .dataframe thead th {\n",
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       "<table border=\"1\" class=\"dataframe\">\n",
       "  <thead>\n",
       "    <tr style=\"text-align: right;\">\n",
       "      <th></th>\n",
       "      <th>Candidate</th>\n",
       "      <th>Party</th>\n",
       "      <th>%</th>\n",
       "      <th>Year</th>\n",
       "      <th>Result</th>\n",
       "    </tr>\n",
       "  </thead>\n",
       "  <tbody>\n",
       "    <tr>\n",
       "      <th>4</th>\n",
       "      <td>Mondale</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>37.6</td>\n",
       "      <td>1984</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>3</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "      <td>58.8</td>\n",
       "      <td>1984</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>6</th>\n",
       "      <td>Dukakis</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>45.6</td>\n",
       "      <td>1988</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>3</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "      <td>58.8</td>\n",
       "      <td>1984</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>6</th>\n",
       "      <td>Dukakis</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>45.6</td>\n",
       "      <td>1988</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>6</th>\n",
       "      <td>Dukakis</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>45.6</td>\n",
       "      <td>1988</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>6</th>\n",
       "      <td>Dukakis</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>45.6</td>\n",
       "      <td>1988</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>0</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "      <td>50.7</td>\n",
       "      <td>1980</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>5</th>\n",
       "      <td>Bush</td>\n",
       "      <td>Republican</td>\n",
       "      <td>53.4</td>\n",
       "      <td>1988</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2</th>\n",
       "      <td>Anderson</td>\n",
       "      <td>Independent</td>\n",
       "      <td>6.6</td>\n",
       "      <td>1980</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2</th>\n",
       "      <td>Anderson</td>\n",
       "      <td>Independent</td>\n",
       "      <td>6.6</td>\n",
       "      <td>1980</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>6</th>\n",
       "      <td>Dukakis</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>45.6</td>\n",
       "      <td>1988</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>3</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "      <td>58.8</td>\n",
       "      <td>1984</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>0</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "      <td>50.7</td>\n",
       "      <td>1980</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>6</th>\n",
       "      <td>Dukakis</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>45.6</td>\n",
       "      <td>1988</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>5</th>\n",
       "      <td>Bush</td>\n",
       "      <td>Republican</td>\n",
       "      <td>53.4</td>\n",
       "      <td>1988</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>0</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "      <td>50.7</td>\n",
       "      <td>1980</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2</th>\n",
       "      <td>Anderson</td>\n",
       "      <td>Independent</td>\n",
       "      <td>6.6</td>\n",
       "      <td>1980</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>4</th>\n",
       "      <td>Mondale</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>37.6</td>\n",
       "      <td>1984</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>4</th>\n",
       "      <td>Mondale</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>37.6</td>\n",
       "      <td>1984</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>0</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "      <td>50.7</td>\n",
       "      <td>1980</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>4</th>\n",
       "      <td>Mondale</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>37.6</td>\n",
       "      <td>1984</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2</th>\n",
       "      <td>Anderson</td>\n",
       "      <td>Independent</td>\n",
       "      <td>6.6</td>\n",
       "      <td>1980</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1</th>\n",
       "      <td>Carter</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>41.0</td>\n",
       "      <td>1980</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1</th>\n",
       "      <td>Carter</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>41.0</td>\n",
       "      <td>1980</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1</th>\n",
       "      <td>Carter</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>41.0</td>\n",
       "      <td>1980</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>0</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "      <td>50.7</td>\n",
       "      <td>1980</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1</th>\n",
       "      <td>Carter</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>41.0</td>\n",
       "      <td>1980</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1</th>\n",
       "      <td>Carter</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>41.0</td>\n",
       "      <td>1980</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>3</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "      <td>58.8</td>\n",
       "      <td>1984</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>6</th>\n",
       "      <td>Dukakis</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>45.6</td>\n",
       "      <td>1988</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>3</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "      <td>58.8</td>\n",
       "      <td>1984</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>6</th>\n",
       "      <td>Dukakis</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>45.6</td>\n",
       "      <td>1988</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2</th>\n",
       "      <td>Anderson</td>\n",
       "      <td>Independent</td>\n",
       "      <td>6.6</td>\n",
       "      <td>1980</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>3</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "      <td>58.8</td>\n",
       "      <td>1984</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>0</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "      <td>50.7</td>\n",
       "      <td>1980</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1</th>\n",
       "      <td>Carter</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>41.0</td>\n",
       "      <td>1980</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2</th>\n",
       "      <td>Anderson</td>\n",
       "      <td>Independent</td>\n",
       "      <td>6.6</td>\n",
       "      <td>1980</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>6</th>\n",
       "      <td>Dukakis</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>45.6</td>\n",
       "      <td>1988</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>4</th>\n",
       "      <td>Mondale</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>37.6</td>\n",
       "      <td>1984</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1</th>\n",
       "      <td>Carter</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>41.0</td>\n",
       "      <td>1980</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>0</th>\n",
       "      <td>Reagan</td>\n",
       "      <td>Republican</td>\n",
       "      <td>50.7</td>\n",
       "      <td>1980</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>4</th>\n",
       "      <td>Mondale</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>37.6</td>\n",
       "      <td>1984</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>4</th>\n",
       "      <td>Mondale</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>37.6</td>\n",
       "      <td>1984</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2</th>\n",
       "      <td>Anderson</td>\n",
       "      <td>Independent</td>\n",
       "      <td>6.6</td>\n",
       "      <td>1980</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>4</th>\n",
       "      <td>Mondale</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>37.6</td>\n",
       "      <td>1984</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>6</th>\n",
       "      <td>Dukakis</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>45.6</td>\n",
       "      <td>1988</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1</th>\n",
       "      <td>Carter</td>\n",
       "      <td>Democratic</td>\n",
       "      <td>41.0</td>\n",
       "      <td>1980</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2</th>\n",
       "      <td>Anderson</td>\n",
       "      <td>Independent</td>\n",
       "      <td>6.6</td>\n",
       "      <td>1980</td>\n",
       "      <td>loss</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>5</th>\n",
       "      <td>Bush</td>\n",
       "      <td>Republican</td>\n",
       "      <td>53.4</td>\n",
       "      <td>1988</td>\n",
       "      <td>win</td>\n",
       "    </tr>\n",
       "  </tbody>\n",
       "</table>\n",
       "</div>"
      ],
      "text/plain": [
       "  Candidate        Party     %  Year Result\n",
       "4   Mondale   Democratic  37.6  1984   loss\n",
       "3    Reagan   Republican  58.8  1984    win\n",
       "6   Dukakis   Democratic  45.6  1988   loss\n",
       "3    Reagan   Republican  58.8  1984    win\n",
       "6   Dukakis   Democratic  45.6  1988   loss\n",
       "6   Dukakis   Democratic  45.6  1988   loss\n",
       "6   Dukakis   Democratic  45.6  1988   loss\n",
       "0    Reagan   Republican  50.7  1980    win\n",
       "5      Bush   Republican  53.4  1988    win\n",
       "2  Anderson  Independent   6.6  1980   loss\n",
       "2  Anderson  Independent   6.6  1980   loss\n",
       "6   Dukakis   Democratic  45.6  1988   loss\n",
       "3    Reagan   Republican  58.8  1984    win\n",
       "0    Reagan   Republican  50.7  1980    win\n",
       "6   Dukakis   Democratic  45.6  1988   loss\n",
       "5      Bush   Republican  53.4  1988    win\n",
       "0    Reagan   Republican  50.7  1980    win\n",
       "2  Anderson  Independent   6.6  1980   loss\n",
       "4   Mondale   Democratic  37.6  1984   loss\n",
       "4   Mondale   Democratic  37.6  1984   loss\n",
       "0    Reagan   Republican  50.7  1980    win\n",
       "4   Mondale   Democratic  37.6  1984   loss\n",
       "2  Anderson  Independent   6.6  1980   loss\n",
       "1    Carter   Democratic  41.0  1980   loss\n",
       "1    Carter   Democratic  41.0  1980   loss\n",
       "1    Carter   Democratic  41.0  1980   loss\n",
       "0    Reagan   Republican  50.7  1980    win\n",
       "1    Carter   Democratic  41.0  1980   loss\n",
       "1    Carter   Democratic  41.0  1980   loss\n",
       "3    Reagan   Republican  58.8  1984    win\n",
       "6   Dukakis   Democratic  45.6  1988   loss\n",
       "3    Reagan   Republican  58.8  1984    win\n",
       "6   Dukakis   Democratic  45.6  1988   loss\n",
       "2  Anderson  Independent   6.6  1980   loss\n",
       "3    Reagan   Republican  58.8  1984    win\n",
       "0    Reagan   Republican  50.7  1980    win\n",
       "1    Carter   Democratic  41.0  1980   loss\n",
       "2  Anderson  Independent   6.6  1980   loss\n",
       "6   Dukakis   Democratic  45.6  1988   loss\n",
       "4   Mondale   Democratic  37.6  1984   loss\n",
       "1    Carter   Democratic  41.0  1980   loss\n",
       "0    Reagan   Republican  50.7  1980    win\n",
       "4   Mondale   Democratic  37.6  1984   loss\n",
       "4   Mondale   Democratic  37.6  1984   loss\n",
       "2  Anderson  Independent   6.6  1980   loss\n",
       "4   Mondale   Democratic  37.6  1984   loss\n",
       "6   Dukakis   Democratic  45.6  1988   loss\n",
       "1    Carter   Democratic  41.0  1980   loss\n",
       "2  Anderson  Independent   6.6  1980   loss\n",
       "5      Bush   Republican  53.4  1988    win"
      ]
     },
     "execution_count": 55,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "elections.query(\"Year < 1992\").sample(50, replace=True)"
   ]
  }
 ],
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