Ch3-3

Author: rambasnet

Ch03-3-Functions-UserDefined.ipynb

@@ -8,16 +8,21 @@
     "- named sequence of statements that execute together to solve some task \n",
     "- primary purpose is to help us break the problem into smaller sub-problems or tasks\n",
     "- two types: fruitful and void/fruitless functions\n",
-    "- must be defined before it can be used\n",
-    "- syntax for a function definition:\n",
+    "- must be defined before it can be used or called (two step process)\n",
+    "- syntax to define a function:\n",
     "```python\n",
     "def functionName( PARAMETER1, PARAMETER2, ... ):\n",
     "    # STATEMENTS\n",
     "    return VALUE\n",
     "```\n",
     "- PARAMETERS and return statements are OPTIONAL\n",
     "- function NAME follows the same rules as a variable/identifier name\n",
-    "- some built-in functions and object methods have been used..."
+    "- some built-in functions and object methods have been used...\n",
+    "- syntax to call function\n",
+    "\n",
+    "```python\n",
+    "VARIABLE = functionName( ARGUMENT1, ARGUMENT2, ...)\n",
+    "```"
    ]
   },
   {
@@ -29,7 +34,7 @@
     "- give you an opportunity to name a group of statements, which makes your program easier to read and debug\n",
     "- can make a program smaller by eliminating repetitive code. Later, if you make a change, you only have to make it in one place\n",
     "- allow you to debug the parts one at a time (in a team) and then assemble them into a working whole\n",
-    "- write once, test, share, and reuse many times (libraries, e.g.)\n"
+    "- write once, test, share, and reuse many times (libraries, e.g.)"
    ]
   },
   {
@@ -41,23 +46,29 @@
     "- call/use function"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## void/fruitless functions"
+   ]
+  },
   {
    "cell_type": "code",
-   "execution_count": 21,
+   "execution_count": 2,
    "metadata": {
     "scrolled": true
    },
    "outputs": [],
    "source": [
     "# Function definition\n",
-    "# void function; returns None by default\n",
     "def greet():\n",
     "    print('Hello World!')"
    ]
   },
   {
    "cell_type": "code",
-   "execution_count": 22,
+   "execution_count": 3,
    "metadata": {
     "scrolled": true
    },
@@ -77,7 +88,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 23,
+   "execution_count": 4,
    "metadata": {
     "scrolled": true
    },
@@ -87,13 +98,14 @@
      "output_type": "stream",
      "text": [
       "Hello World!\n",
-      "None\n"
+      "a = None\n"
      ]
     }
    ],
    "source": [
+    "# void function; returns None by default\n",
     "a = greet() # returned value\n",
-    "print(a)"
+    "print('a =', a)"
    ]
   },
   {
@@ -165,7 +177,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "## passing data\n",
+    "## passing data/arguments to functions\n",
     "- functions are subprograms that may need external data to work with\n",
     "- one can pass data to functions via parameters/arguments\n",
     "- can provide default values to parameters"
@@ -381,8 +393,8 @@
    "source": [
     "def add(num1, num2):\n",
     "    \"\"\"\n",
-    "    takes take numeric arguments, num1 and num2\n",
-    "    returns the sum of num1 and num2\n",
+    "    takes two numeric arguments: num1 and num2\n",
+    "    calculates and returns the sume of num1 and num2\n",
     "    \"\"\"\n",
     "    total = num1 + num2\n",
     "    return total"
@@ -571,7 +583,7 @@
    },
    "source": [
     "## pass by value\n",
-    "- passing immutable objects (string, int, float) as arguments to functions"
+    "- passing immutable variables (string, int, float) as arguments to functions by copying them"
    ]
   },
   {