Solve issues with new ex2_0_1

- count the  number of words on the words list not the lyrics because
character like ‘i’ will be counted many times
- change wording for 2.1.1 c. if the sequence passed contains base N,
use the mean...
- Improve explanation of arguments of functions
- Remove format string in day2 session3

Author: pajanne

Diff for: Introduction_to_python_day_2_session_1.ipynb

@@ -358,7 +358,7 @@
     "</table>\n",
     "\n",
     "\n",
-    "- c. If the sequence passed in above contains `N` bases, use the mean weight of the other bases as the weight."
+    "- c. If the sequence passed contains base `N`, use the mean weight of the other bases as the weight of base `N`."
    ]
   },
   {
@@ -455,6 +455,8 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
+    "### Mandatory arguments\n",
+    "\n",
     "The arguments we have passed to functions so far have all been _mandatory_, if we do not supply them or if supply the wrong number of arguments python will throw an error also called an exception:"
    ]
   },
@@ -467,8 +469,9 @@
    "outputs": [],
    "source": [
     "def square(number):\n",
-    "  y = number*number\n",
-    "  return y"
+    "    # one mandatory argument\n",
+    "    y = number*number\n",
+    "    return y"
    ]
   },
   {
@@ -486,7 +489,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "Mandatory arguments are assumed to come in the same order as the arguments in the function definition, but you can also opt to specify the arguments using the argument names as _keywords_, supplying the values corresponding to each keyword with a `=` sign."
+    "**Mandatory arguments are assumed to come in the same order as the arguments in the function definition**, but you can also opt to specify the arguments using the argument names as _keywords_, supplying the values corresponding to each keyword with a `=` sign."
    ]
   },
   {
@@ -509,6 +512,7 @@
    "outputs": [],
    "source": [
     "def repeat(seq, n):\n",
+    "    # two mandatory arguments\n",
     "    result = ''\n",
     "    for i in range(0,n):\n",
     "        result += seq\n",
@@ -533,13 +537,14 @@
    },
    "outputs": [],
    "source": [
-    "print(repeat(seq=\"CTA\", 3))"
+    "print(repeat(seq=\"CTA\", n=3))"
    ]
   },
   {
    "cell_type": "markdown",
    "metadata": {},
    "source": [
+    "### Arguments with default values\n",
     "Sometimes it is useful to give some arguments a default value that the caller can override, but which will be used if the caller does not supply a value for this argument. We can do this by assigning some value to the named argument with the `=` operator in the function definition."
    ]
   },
@@ -579,14 +584,17 @@
     "    \n",
     "myFunction()\n",
     "myFunction()\n",
+    "myFunction()\n",
+    "myFunction([])\n",
+    "myFunction([])\n",
     "myFunction([])"
    ]
   },
   {
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "One can either create a \"new\" default variable every time a function is run:"
+    "... or avoid modifying *mutable* default arguments."
    ]
   },
   {
@@ -597,27 +605,25 @@
    },
    "outputs": [],
    "source": [
-    "def myFunction(parameters=None):\n",
-    "    \n",
-    "    if parameters is None:\n",
-    "        parameters = []\n",
-    "        \n",
+    "def myFunction(parameters):\n",
+    "    # one mandatory argument without default value\n",
     "    parameters.append( 100 )\n",
     "    print(parameters)\n",
     "    \n",
-    "myFunction()\n",
-    "myFunction()\n",
-    "myFunction([80])\n",
-    "myFunction([80])"
+    "my_list = []\n",
+    "myFunction(my_list)\n",
+    "myFunction(my_list)\n",
+    "myFunction(my_list)\n",
+    "my_new_list = []\n",
+    "myFunction(my_new_list)"
    ]
   },
   {
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "... or avoid modifying *mutable* default arguments.\n",
-    "\n",
-    "By using the `+` operator which returns the result of the expression as a new value, instead of `list.extend()` that modified the list in-place and returns nothing."
+    "### Position of mandatory arguments\n",
+    "Arrange function arguments so that *mandatory* arguments come first:"
    ]
   },
   {
@@ -628,19 +634,19 @@
    },
    "outputs": [],
    "source": [
-    "def myFunction(parameters=[]):\n",
-    "    results = parameters + [100]\n",
-    "    print(results)\n",
+    "def runSimulation(initialTemperature, nsteps=1000):\n",
+    "    # one mandatory argument followed by one with default value\n",
+    "    print(\"Running simulation starting at\", initialTemperature, \"K and doing\", nsteps, \"steps\")\n",
     "    \n",
-    "myFunction()\n",
-    "myFunction()"
+    "runSimulation(300, 500)\n",
+    "runSimulation(300)"
    ]
   },
   {
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "Arrange function arguments so that *mandatory* arguments come first:"
+    "As before, no positional argument can appear after a keyword argument, and all required arguments must still be provided."
    ]
   },
   {
@@ -651,11 +657,7 @@
    },
    "outputs": [],
    "source": [
-    "def runSimulation(initialTemperature, nsteps=1000):\n",
-    "    print(\"Running simulation starting at\", initialTemperature, \"K and doing\", nsteps, \"steps\")\n",
-    "    \n",
-    "runSimulation(300, 500)\n",
-    "runSimulation(300)"
+    "runSimulation( nsteps=100, initialTemperature=300 )"
    ]
   },
   {
@@ -666,15 +668,7 @@
    },
    "outputs": [],
    "source": [
-    "def badFunction(nsteps=1000, initialTemperature):\n",
-    "    pass\n"
-   ]
-  },
-  {
-   "cell_type": "markdown",
-   "metadata": {},
-   "source": [
-    "As before, no positional argument can appear after a keyword argument, and all required arguments must still be provided."
+    "runSimulation( initialTemperature=300 )"
    ]
   },
   {
@@ -685,7 +679,7 @@
    },
    "outputs": [],
    "source": [
-    "runSimulation( nsteps=100, 300 )"
+    "runSimulation( nsteps=100 ) # Error: missing required argument 'initialTemperature'"
    ]
   },
   {
@@ -696,7 +690,7 @@
    },
    "outputs": [],
    "source": [
-    "runSimulation( nsteps=100 )"
+    "runSimulation( nsteps=100, 300 ) # Error: positional argument follows keyword argument"
    ]
   },
   {
@@ -714,7 +708,14 @@
    },
    "outputs": [],
    "source": [
-    "runSimulation( initialTemperature=300, numSteps=100 )"
+    "runSimulation( initialTemperature=300, numSteps=100 ) # Error: unexpected keyword argument 'numSteps'"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "Function cannot be defined with mandatory arguments after default ones."
    ]
   },
   {
@@ -725,11 +726,8 @@
    },
    "outputs": [],
    "source": [
-    "def runSimulation(initialTemperature, nsteps=1000):\n",
-    "    print(\"Running simulation starting at\", initialTemperature, \"K and doing\", nsteps, \"steps\")\n",
-    "    \n",
-    "runSimulation(initialTemperature=300, nsteps=500)\n",
-    "runSimulation(initialTemperature=300)"
+    "def badFunction(nsteps=1000, initialTemperature):\n",
+    "    pass"
    ]
   },
   {

Diff for: Introduction_to_python_day_2_session_3.ipynb

@@ -218,10 +218,10 @@
    "source": [
     "# one line at a time\n",
     "fileObj = open( \"data/datafile.txt\" )\n",
-    "print(\"1st line: %r\" % fileObj.readline())\n",
-    "print(\"2nd line: %r\" % fileObj.readline())\n",
-    "print(\"3rd line: %r\" % fileObj.readline())\n",
-    "print(\"4th line: %r\" % fileObj.readline())\n",
+    "print(\"1st line:\", fileObj.readline())\n",
+    "print(\"2nd line:\", fileObj.readline())\n",
+    "print(\"3rd line:\", fileObj.readline())\n",
+    "print(\"4th line:\", fileObj.readline())\n",
     "fileObj.close()"
    ]
   },

Diff for: solutions/ex2_0_1.py

@@ -37,6 +37,9 @@
 And the world will live as one
 """
 
+# Change all character to lower ones
+lyrics = lyrics.lower()
+
 # Split into words
 words = lyrics.split()
 # Print the total number of words
@@ -49,11 +52,11 @@
 # Calculate the frequency of each word and store the result into a dictionary
 results = {}
 for w in unique_words:
-    results[w.lower()] = lyrics.count(w)
+    results[w.lower()] = words.count(w)
 
 # Print each unique word along with its frequency
 for r in results:
-    print(results[r], '\ttimes for word:', r)
+    print(results[r], '\t', r)
 
 # Find the most frequent word in the song
 most_frequent = 0
@@ -63,4 +66,4 @@
         most_frequent_word = r
 
 # Print the most frequent word with its frequency
-print(most_frequent_word, 'is the most frequent word being used', most_frequent, 'times.')
+print('"', most_frequent_word, '" is the most frequent word being used', most_frequent, 'times.')