{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Conditionals and their caveats"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# `==` and `is`\n",
    "[Condensed from this SO thread](http://stackoverflow.com/questions/132988/is-there-a-difference-between-and-is-in-python)    \n",
    "\n",
    "The rule of thumb to when to use `==` or `is`.\n",
    "- `==` is for value equality. Use to know if two objects *have the same value*.\n",
    "- `is` is for reference equality. Use to know if two references *refer to the same object*.\n",
    "\n",
    "OR more compactly;\n",
    "- `is` - identity testing,\n",
    "- `==` - equality testing. "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "True"
      ]
     },
     "execution_count": 2,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "a = [1, 2, 3]\n",
    "b = a\n",
    "b is a "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "True"
      ]
     },
     "execution_count": 3,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "b == a"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "False"
      ]
     },
     "execution_count": 4,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "b = a[:]\n",
    "b is a"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "True"
      ]
     },
     "execution_count": 5,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "b == a"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "False\n",
      "True\n"
     ]
    }
   ],
   "source": [
    "# Also and most annoyingly;\n",
    "print([] is [])\n",
    "print([] == []) "
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# The `while` statement"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "def funzo():\n",
    "    contin = input(\"Are you having fun yet?(Y/N) \")\n",
    "    while contin == \"N\":\n",
    "        contin = input(\"I'm sorry! :( \\n Are you having fun now? (Y/N) \")\n",
    "    while contin == \"Y\":\n",
    "        return \"Good! I hope your happy now.\""
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Are you having fun yet?(Y/N) N\n",
      "I'm sorry! :( \n",
      " Are you having fun now? (Y/N) N\n",
      "I'm sorry! :( \n",
      " Are you having fun now? (Y/N) N\n",
      "I'm sorry! :( \n",
      " Are you having fun now? (Y/N) Y\n"
     ]
    },
    {
     "data": {
      "text/plain": [
       "'Good! I hope your happy now.'"
      ]
     },
     "execution_count": 2,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "funzo()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": []
  }
 ],
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   "codemirror_mode": {
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