added loops

Author: lu-kas

book/content/tools/03_analysis/01_python.ipynb

@@ -2,15 +2,15 @@
  "cells": [
   {
    "cell_type": "markdown",
-   "id": "7fbc4c40",
+   "id": "3561769f",
    "metadata": {},
    "source": [
     "# Python"
    ]
   },
   {
    "cell_type": "markdown",
-   "id": "6d82b2da",
+   "id": "79f02d37",
    "metadata": {},
    "source": [
     "## Disclaimer\n",
@@ -24,7 +24,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "25a89cd4",
+   "id": "8d01e2d6",
    "metadata": {},
    "source": [
     "## Why Python?\n",
@@ -48,7 +48,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "757dc2da",
+   "id": "0513894c",
    "metadata": {},
    "source": [
     "## Basics\n",
@@ -122,7 +122,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "d7c9a774",
+   "id": "b0c01e83",
    "metadata": {},
    "source": [
     "### Operators\n",
@@ -140,7 +140,7 @@
   {
    "cell_type": "code",
    "execution_count": 1,
-   "id": "789d1369",
+   "id": "8554f54a",
    "metadata": {},
    "outputs": [
     {
@@ -162,7 +162,7 @@
   {
    "cell_type": "code",
    "execution_count": 2,
-   "id": "3fbcd67e",
+   "id": "c0c3e574",
    "metadata": {},
    "outputs": [
     {
@@ -183,7 +183,7 @@
   {
    "cell_type": "code",
    "execution_count": 3,
-   "id": "42193ad1",
+   "id": "98d59155",
    "metadata": {},
    "outputs": [
     {
@@ -204,7 +204,7 @@
   {
    "cell_type": "code",
    "execution_count": 4,
-   "id": "eb2c1de9",
+   "id": "5a24834f",
    "metadata": {},
    "outputs": [
     {
@@ -224,7 +224,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "75e7101f",
+   "id": "717a792a",
    "metadata": {},
    "source": [
     "### Variables\n",
@@ -243,7 +243,7 @@
   {
    "cell_type": "code",
    "execution_count": 6,
-   "id": "ca738e52",
+   "id": "0563eb8f",
    "metadata": {},
    "outputs": [
     {
@@ -267,7 +267,7 @@
   {
    "cell_type": "code",
    "execution_count": 7,
-   "id": "6876244a",
+   "id": "6b55146b",
    "metadata": {},
    "outputs": [
     {
@@ -289,7 +289,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "7b8f2503",
+   "id": "8d1935a6",
    "metadata": {},
    "source": [
     "There are a few basic data types in Python:\n",
@@ -302,7 +302,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "065d39d0",
+   "id": "529d01c9",
    "metadata": {},
    "source": [
     "### Functions\n",
@@ -321,7 +321,7 @@
   {
    "cell_type": "code",
    "execution_count": 8,
-   "id": "274bc7f3",
+   "id": "1f5e00a8",
    "metadata": {},
    "outputs": [
     {
@@ -346,7 +346,7 @@
   {
    "cell_type": "code",
    "execution_count": 11,
-   "id": "1c96e931",
+   "id": "0be9003a",
    "metadata": {},
    "outputs": [
     {
@@ -369,7 +369,7 @@
   {
    "cell_type": "code",
    "execution_count": 14,
-   "id": "4ddd5d5c",
+   "id": "0f34eee1",
    "metadata": {},
    "outputs": [
     {
@@ -393,7 +393,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "d757141a",
+   "id": "831d2b85",
    "metadata": {},
    "source": [
     "## Lists\n",
@@ -408,7 +408,7 @@
   {
    "cell_type": "code",
    "execution_count": 15,
-   "id": "89da7bac",
+   "id": "0acc93fa",
    "metadata": {},
    "outputs": [
     {
@@ -429,7 +429,7 @@
   {
    "cell_type": "code",
    "execution_count": 16,
-   "id": "5cfa87a8",
+   "id": "db2d9595",
    "metadata": {},
    "outputs": [
     {
@@ -452,7 +452,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "0a40d867",
+   "id": "fbb59661",
    "metadata": {},
    "source": [
     "It is possible to access individual elements of a list, either for reading or changing its value. To do so, the element is addressed by its index, which starts at zero. The syntax for this is `list[index]`. To reference the elements starting at the last one, negative indices are used. Here the last element has the index -1."
@@ -461,7 +461,7 @@
   {
    "cell_type": "code",
    "execution_count": 19,
-   "id": "cb179a79",
+   "id": "ebdf8692",
    "metadata": {},
    "outputs": [
     {
@@ -485,7 +485,7 @@
   {
    "cell_type": "code",
    "execution_count": 20,
-   "id": "1a455b04",
+   "id": "92a6d554",
    "metadata": {},
    "outputs": [
     {
@@ -510,7 +510,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "794632e6",
+   "id": "6b4bebff",
    "metadata": {},
    "source": [
     "## Strings\n",
@@ -527,7 +527,7 @@
   {
    "cell_type": "code",
    "execution_count": 24,
-   "id": "f704d8c9",
+   "id": "a6c0618d",
    "metadata": {},
    "outputs": [
     {
@@ -549,7 +549,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "2435c155",
+   "id": "16e8ea15",
    "metadata": {},
    "source": [
     "To incorporate variable values into strings, formatted strings (f-strings) can be used. They allow to reference variable values and control their string representation. The placeholder is defined with `{variable_name}` and the f-string is declared with `f''` or `f\"\"`."
@@ -558,7 +558,7 @@
   {
    "cell_type": "code",
    "execution_count": 26,
-   "id": "a2729b1c",
+   "id": "240870f2",
    "metadata": {},
    "outputs": [
     {
@@ -586,19 +586,134 @@
   },
   {
    "cell_type": "markdown",
-   "id": "72c94c38",
+   "id": "0946d715",
    "metadata": {},
    "source": [
     "## Flow Control\n",
     "\n",
+    "There exist two main structures, which are common in many programming languages and allow to build a complex execution flow.\n",
+    "\n",
+    "* **Loops** repeat a set of expressions (loop body) for a given loop variable. The value of the loop variable iterates throug a list of values.\n",
+    "\n",
+    "* **Branching** allows to execute expressions depending on a condition. \n",
+    "\n",
     "### Loops\n",
     "\n",
+    "The basic structure of a loop is\n",
+    "\n",
+    "```python\n",
+    "# loop header\n",
+    "for loop_variable in loop_values:\n",
+    "    # loop body\n",
+    "    loop_body()\n",
+    "```\n",
+    "\n",
+    "Here, the name of the loop variable can be freely chosen and the loop body may consist of any number of expressions. The syntax for a loop definition includes the keywords `for` and `in`, while the header is closed with a `:`. The loop body is intended by one level (e.g. 4 spaces or a single tab)."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 27,
+   "id": "d0f68bf8",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "4 16\n",
+      "7 49\n",
+      "2 4\n",
+      "9 81\n"
+     ]
+    }
+   ],
+   "source": [
+    "# Loop example 1\n",
+    "\n",
+    "for i in [4,7,2,9]:\n",
+    "    print(i, i**2)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 29,
+   "id": "fc0a60ff",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "0 0\n",
+      "1 10\n",
+      "2 20\n",
+      "3 30\n",
+      "4 40\n",
+      "5 50\n",
+      "6 60\n",
+      "7 70\n",
+      "8 80\n",
+      "9 90\n"
+     ]
+    }
+   ],
+   "source": [
+    "# Loop example 2\n",
+    "\n",
+    "for j in range(10):\n",
+    "    print(j, j*10)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "4158a94e",
+   "metadata": {},
+   "source": [
+    "The build-in function [`range()`](https://docs.python.org/3/library/functions.html#func-range) is often used in the context of loops to generate a structured sequence of values to be looped over. It can take up to three arguments (start, stop, step) to control the created sequance."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 30,
+   "id": "a4d6f177",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "10\n",
+      "12\n",
+      "14\n",
+      "16\n",
+      "18\n",
+      "20\n",
+      "22\n",
+      "24\n",
+      "26\n",
+      "28\n"
+     ]
+    }
+   ],
+   "source": [
+    "# Range example\n",
+    "\n",
+    "for k in range(10, 30, 2):\n",
+    "    print(k)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "db4cbea3",
+   "metadata": {},
+   "source": [
     "### Branching"
    ]
   },
   {
    "cell_type": "markdown",
-   "id": "e8eea953",
+   "id": "27a4dd9c",
    "metadata": {},
    "source": [
     "## Modules\n",