Week-02-01-Conditional Statements

{
 "metadata": {
  "name": ""
 },
 "nbformat": 3,
 "nbformat_minor": 0,
 "worksheets": [
  {
   "cells": [
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "#  Slide 3\n",
      "# 2 == 2 evaluates to True\n",
      "2 == 2"
     ],
     "language": "python",
     "metadata": {},
     "outputs": []
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "#  Slide 4\n",
      "import random\n",
      "number = random.randint(0,20)\n",
      "guess = int(input('Enter an integer : '))\n",
      "if guess == number:\n",
      "    print('Congratulations, you guessed it.')\n",
      "elif guess < number:\n",
      "    print('No, it is higher than that')\n",
      "else:\n",
      "    print('No, it is lower than that')"
     ],
     "language": "python",
     "metadata": {},
     "outputs": []
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "#  Slide 6\n",
      "a = 1\n",
      "b = 2\n",
      "c = 3\n",
      "print (a or b or c)\n",
      "\n",
      "print (a and b and c)\n",
      "\n",
      "print (b or a and c)"
     ],
     "language": "python",
     "metadata": {},
     "outputs": []
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "# Slide 9 \n",
      "# Firstr try this and you get an error because of division by zero\n",
      "# T\n",
      "(x,y) = (5,0)\n",
      "z = x/y"
     ],
     "language": "python",
     "metadata": {},
     "outputs": []
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "# Slide 9 (i)\n",
      "(x,y) = (5,0)\n",
      "try:\n",
      "    z = x/y\n",
      "except ZeroDivisionError:\n",
      "    print \"divide by zero\"\n",
      "\n",
      "# Slide 9 (ii)\n",
      "(x,y) = (5,0)\n",
      "try:\n",
      "    z = x/y\n",
      "except ZeroDivisionError, e:\n",
      "    z = e \n",
      "    print z\n",
      "\n",
      "# Slide 9 (iii)\n",
      "(x,y) = (5,0)\n",
      "try:\n",
      "    z = x/y\n",
      "except Exception, e:\n",
      "    print str(e)\n",
      "    print repr(e)"
     ],
     "language": "python",
     "metadata": {},
     "outputs": []
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "# Slide 10\n",
      "# quadratic.py\n",
      "#    A program that computes the real roots of a quadratic equation.\n",
      "#    Illustrates use of the math library.\n",
      "#    Note: This program crashes if the equation has no real roots.\n",
      "import math\n",
      "print \"This program finds the real solutions to a quadratic\"\n",
      "print\n",
      "a, b, c = input(\"Please enter the coefficients (a, b, c): \")\n",
      "discRoot = math.sqrt(b * b - 4 * a * c)\n",
      "root1 = (-b + discRoot) / (2 * a)\n",
      "root2 = (-b - discRoot) / (2 * a)\n",
      "print\n",
      "print \"The solutions are:\", root1, root2"
     ],
     "language": "python",
     "metadata": {},
     "outputs": []
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "# Slide 10\n",
      "# quadratic2.py\n",
      "#    A program that computes the real roots of a quadratic equation.\n",
      "#    Bad version using a simple if to avoid program crash\n",
      "import math \n",
      "print \"This program finds the real solutions to a quadratic\\n\"\n",
      "a, b, c = input(\"Please enter the coefficients (a, b, c): \")\n",
      "discrim = b * b - 4 * a * c\n",
      "if discrim >= 0:\n",
      "    discRoot = math.sqrt(discrim)\n",
      "    root1 = (-b + discRoot) / (2 * a)\n",
      "    root2 = (-b - discRoot) / (2 * a)\n",
      "    print \"\\nThe solutions are:\", root1, root2\n"
     ],
     "language": "python",
     "metadata": {},
     "outputs": []
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "# Slide 10\n",
      "# quadratic3.py\n",
      "#    A program that computes the real roots of a quadratic equation.\n",
      "#    Illustrates use of a two-way decision\n",
      "import math\n",
      "print \"This program finds the real solutions to a quadratic\\n\"\n",
      "a, b, c = input(\"Please enter the coefficients (a, b, c): \")\n",
      "discrim = b * b - 4 * a * c   \n",
      "if discrim < 0:\n",
      "    print \"\\nThe equation has no real roots!\"\n",
      "else:\n",
      "    discRoot = math.sqrt(b * b - 4 * a * c)\n",
      "    root1 = (-b + discRoot) / (2 * a)\n",
      "    root2 = (-b - discRoot) / (2 * a)\n",
      "    print \"\\nThe solutions are:\", root1, root2"
     ],
     "language": "python",
     "metadata": {},
     "outputs": []
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "# Slide 10\n",
      "# quadratic4.py\n",
      "#    A program that computes the real roots of a quadratic equation.\n",
      "#    Illustrates use of a multi-way decision\n",
      "import math\n",
      "print \"This program finds the real solutions to a quadratic\\n\"\n",
      "a, b, c = input(\"Please enter the coefficients (a, b, c): \")\n",
      "discrim = b * b - 4 * a * c\n",
      "if discrim < 0:\n",
      "    print \"\\nThe equation has no real roots!\"\n",
      "elif discrim == 0:\n",
      "    root = -b / (2 * a)\n",
      "    print \"\\nThere is a double root at\", root\n",
      "else:\n",
      "    discRoot = math.sqrt(b * b - 4 * a * c)\n",
      "    root1 = (-b + discRoot) / (2 * a)\n",
      "    root2 = (-b - discRoot) / (2 * a)\n",
      "    print \"\\nThe solutions are:\", root1, root2\n",
      " "
     ],
     "language": "python",
     "metadata": {},
     "outputs": []
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "# Slide 10\n",
      "# quadratic5.py\n",
      "#    A program that computes the real roots of a quadratic equation.\n",
      "#    Illustrates exception handling to avoid crash on bad inputs\n",
      "import math\n",
      "print \"This program finds the real solutions to a quadratic\\n\"\n",
      "try:\n",
      "    a, b, c = input(\"Please enter the coefficients (a, b, c): \")\n",
      "    discRoot = math.sqrt(b * b - 4 * a * c)\n",
      "    root1 = (-b + discRoot) / (2 * a)\n",
      "    root2 = (-b - discRoot) / (2 * a)\n",
      "    print \"\\nThe solutions are:\", root1, root2\n",
      "except ValueError:\n",
      "    print \"\\nNo real roots\""
     ],
     "language": "python",
     "metadata": {},
     "outputs": []
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "# Slide 10\n",
      "# quadratic6.py\n",
      "#    A program that computes the real roots of a quadratic equation.\n",
      "#    Illustrates robust exception handling to avoid crash on bad inputs\n",
      "import math\n",
      "print \"This program finds the real solutions to a quadratic\\n\"\n",
      "try:\n",
      "    a, b, c = input(\"Please enter the coefficients (a, b, c): \")\n",
      "    discRoot = math.sqrt(b * b - 4 * a * c)\n",
      "    root1 = (-b + discRoot) / (2 * a)\n",
      "    root2 = (-b - discRoot) / (2 * a)\n",
      "    print \"\\nThe solutions are:\", root1, root2\n",
      "except ValueError, excObj:\n",
      "    msg = str(excObj)\n",
      "    if msg == \"math domain error\":\n",
      "        print \"\\nNo Real Roots\"\n",
      "    elif msg == \"unpack tuple of wrong size\":\n",
      "        print \"\\nYou didn't give me the right number of coefficients.\"\n",
      "    else:\n",
      "        print \"\\nSomething went wrong, sorry!\"\n",
      "except NameError:\n",
      "    print \"\\nYou didn't enter three numbers.\"\n",
      "except TypeError:\n",
      "    print \"\\nYour inputs were not all numbers.\"\n",
      "except SyntaxError:\n",
      "    print \"\\nYour input was not in the correct form. Missing comma(s), perhaps?\"\n",
      "except:\n",
      "    print \"\\nSomething went wrong, sorry!\""
     ],
     "language": "python",
     "metadata": {},
     "outputs": []
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "# Slide 11\n",
      "# ***** Do this in spyder ******\n",
      "\n",
      "# first.py\n",
      "# Save this file in a separate folder\n",
      "print \"Hi ... in FIRST\"\n",
      "\n",
      "if __name__ == \"__main__\":\n",
      "    print \"Program is running independently\"\n",
      "else:\n",
      "    print \"Program running as an imported module\"\n",
      "    \n",
      "\n",
      "# second.py\n",
      "# Save this file in the same folder as you saved first.py\n",
      "import first\n",
      "\n",
      "print \"Hi ... in SECOND\"\n",
      "\n",
      "if __name__ == \"__main__\":\n",
      "    print \"Program is running independently\"\n",
      "else:\n",
      "    print \"Program running as an imported module\"\n",
      "\n",
      "    \n",
      "# Now run first.py\n",
      "# Then run second.py"
     ],
     "language": "python",
     "metadata": {},
     "outputs": []
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [],
     "language": "python",
     "metadata": {},
     "outputs": []
    }
   ],
   "metadata": {}
  }
 ]
}