Part 3 cupcake tally rewrite.

Author: audreyfeldroy

part-3.ipynb

@@ -10,7 +10,7 @@
    "name": "python2"
   },
   "name": "",
-  "signature": "sha256:71c98cee8fe96271cc8983aae5b8d91c4d35188a06dd6e0fce00a96d7bd13e92"
+  "signature": "sha256:ee94c8f65b24aca6551d49f1d80ebf2b4fae52fbbda61e090166f59ccddb81b8"
  },
  "nbformat": 3,
  "nbformat_minor": 0,
@@ -647,81 +647,151 @@
      "level": 2,
      "metadata": {},
      "source": [
-      "Example: Cupcake Count"
+      "Example: Cupcake Tally"
      ]
     },
     {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
-      "Okay, we've explored functions that:\n",
+      "So far we've explored functions that:\n",
       "* Take strings or other values as input\n",
-      "* Print strings\n",
-      "\n",
-      "Now, let's create a function that:\n",
-      "* Takes a number as input\n",
-      "* Returns a number"
+      "* Print strings"
      ]
     },
     {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
-      "So let's create a new function, `cupcake_count`. It will return a value to where the function was initially called.\n",
+      "Let's create a new function, `cupcake_tally()`. This function will be different from the others that I covered. Rather than just printing stuff, it'll return a value when called.\n",
       "\n",
-      "We'll multiply the number of guests by two and return the result because each guest wants to eat two cupcakes."
+      "A good birthday party should allocate:\n",
+      "* 2 cupcakes per guest\n",
+      "* 13 cupcakes for the birthday person, because if it's your birthday, you should be allowed to eat a baker's dozen of cupcakes."
      ]
     },
     {
      "cell_type": "code",
      "collapsed": false,
      "input": [
-      "def cupcake_count(guests):\n",
+      "def cupcake_tally(guests):\n",
       "    \"\"\" Given number of party guests, returns how many cupcakes are needed. \"\"\"\n",
-      "    return 2 * guests"
+      "    return 2 * guests + 13"
      ],
      "language": "python",
      "metadata": {},
      "outputs": [],
-     "prompt_number": 58
+     "prompt_number": 64
     },
     {
-     "cell_type": "heading",
-     "level": 1,
+     "cell_type": "markdown",
      "metadata": {},
      "source": [
-      "print(\"We need to make \" + str(cupcake_count(10)) + \" cupcakes.\")"
+      "How many cupcakes do we need for a party with 30 guests?"
      ]
     },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "cupcake_tally(30)"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "metadata": {},
+       "output_type": "pyout",
+       "prompt_number": 65,
+       "text": [
+        "73"
+       ]
+      }
+     ],
+     "prompt_number": 65
+    },
     {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
-      "Ok, so we call our function, get_cupcake_count, and pass in the integer 10 as the value of the parameter, 'guests'. \n",
-      "\n",
-      "Then we multiply the number of guests by 2 and return the result back to where the function was initially called. \n",
-      "\n",
-      "Lastly, it prints out the returned integer value of 20."
+      "What about if I'm celebrating my birthday at home with just my husband, Daniel?"
      ]
     },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "cupcake_tally(guests=1)"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "metadata": {},
+       "output_type": "pyout",
+       "prompt_number": 69,
+       "text": [
+        "15"
+       ]
+      }
+     ],
+     "prompt_number": 69
+    },
     {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
-      "Note if you are wondering what the str() function is... Python does not allow us to concatenate strings with integers and will tell you so. \n",
+      "Ooh, 15 cupcakes sounds about right for our little party, yeah? ;)\n",
       "\n",
-      "We need to convert the integer with the string function to convert the integer into a string object"
+      "Notice how we explicitly named the `guests` parameter in that example."
+     ]
+    },
+    {
+     "cell_type": "heading",
+     "level": 3,
+     "metadata": {},
+     "source": [
+      "Printing the return value"
      ]
     },
     {
      "cell_type": "code",
      "collapsed": false,
      "input": [
-      "print(\"We need to make \" + str(get_cupcake_count(10)) + \" cupcakes.\")"
+      "cupcakes = cupcake_tally(10)\n",
+      "print(\"We need to make {0} cupcakes.\".format(cupcakes))"
      ],
      "language": "python",
      "metadata": {},
-     "outputs": []
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "We need to make 33 cupcakes.\n"
+       ]
+      }
+     ],
+     "prompt_number": 70
+    },
+    {
+     "cell_type": "markdown",
+     "metadata": {},
+     "source": [
+      "We call our function, `cupcake_tally()`, and pass in 10 as the value of `guests`. \n",
+      "\n",
+      "`cupcake_tally(10)` returns 33, which gets stored in the `cupcakes` variable.\n",
+      "\n",
+      "Lastly, we print \"We need to make 33 cupcakes.\" using Python string formatting."
+     ]
+    },
+    {
+     "cell_type": "heading",
+     "level": 3,
+     "metadata": {},
+     "source": [
+      "Multiple function arguments"
+     ]
     },
     {
      "cell_type": "markdown",
@@ -736,28 +806,41 @@
      "cell_type": "code",
      "collapsed": false,
      "input": [
-      "def get_cupcake_count(cupcakes, guests):   \n",
-      "    return cupcakes * guests"
+      "def cupcake_tally(cupcakes, guests):   \n",
+      "    return cupcakes * guests + 13"
      ],
      "language": "python",
      "metadata": {},
-     "outputs": []
+     "outputs": [],
+     "prompt_number": 71
     },
     {
      "cell_type": "code",
      "collapsed": false,
      "input": [
-      "print(get_cupcake_count(4, 15))"
+      "cupcake_tally(4, 15)"
      ],
      "language": "python",
      "metadata": {},
-     "outputs": []
+     "outputs": [
+      {
+       "metadata": {},
+       "output_type": "pyout",
+       "prompt_number": 73,
+       "text": [
+        "73"
+       ]
+      }
+     ],
+     "prompt_number": 73
     },
     {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
-      "Note that we have a 'cupcakes' parameter as well as a 'guests' parameter. Our function is called and passes in two integer values of 4 and 15. It then prints out the returned result, 60."
+      "Note that we have 2 parameters now: `cupcakes` and `guests`\n",
+      "\n",
+      "Our function is called and passes in two values of 4 and 15. It returns 73."
      ]
     },
     {