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 },
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  {
   "cells": [
    {
     "cell_type": "heading",
     "level": 1,
     "metadata": {},
     "source": [
      "Playing with files, strings and dictionary"
     ]
    },
    {
     "cell_type": "markdown",
     "metadata": {},
     "source": [
      "#### Problem\n",
      "Write a code which creates a phone book. The phone book is stored in a file with the number in the beginning and rest being the name. This makes it easy to separate the number from the name using a split command.\n",
      "\n",
      "When you start the program it drops to a prompt. Say \"phone > \". The enter command creates a new entry. name or part of the name of a person return the number. If the part matches multiple names it returns all the matches."
     ]
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Using dictionary"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "phonedir = {}\n",
      "storefile = \"phone.txt\""
     ],
     "language": "python",
     "metadata": {},
     "outputs": [],
     "prompt_number": 1
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "def load_directory() :\n",
      "    f = open(storefile, 'r')\n",
      "    for line in f :\n",
      "        words = line.split()\n",
      "        phno = words[0]\n",
      "        name = ' '.join(words[1:])\n",
      "        phonedir[name] = int(phno)\n",
      "    f.close()\n",
      "    return None"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [],
     "prompt_number": 2
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "if __name__ == '__main__' :\n",
      "    print \"Checking load_directory.\"\n",
      "    fw = open(storefile, 'w')\n",
      "    fw.write(\"9840336105 Abc Def\\n\")\n",
      "    fw.write(\"9869369319 Ghi Jkl\\n\")\n",
      "    fw.close()\n",
      "    \n",
      "    load_directory()\n",
      "    print phonedir"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "Checking load_directory.\n",
        "{'Abc Def': 9840336105, 'Ghi Jkl': 9869369319}\n"
       ]
      }
     ],
     "prompt_number": 3
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "def enter_name(name, number) :\n",
      "    phonedir[name] = number\n",
      "    return None"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [],
     "prompt_number": 4
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "def save_phone_dir() :\n",
      "    f = open(storefile, 'w')\n",
      "    for e in sorted(phonedir) :\n",
      "        write_string = '%d %s\\n' % (phonedir[e], e)\n",
      "        f.write(write_string)\n",
      "    f.close()\n",
      "    return None"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [],
     "prompt_number": 5
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "if __name__ == '__main__' :\n",
      "    print \"Checking enter_name and save_phone_dir\"\n",
      "    enter_name(\"Mno Pqr\", 681990341)\n",
      "    save_phone_dir()\n",
      "    load_directory()\n",
      "    print phonedir\n",
      "    f = open(storefile, 'r')\n",
      "    for line in f :\n",
      "        print line,\n",
      "    print\n",
      "    f.close()"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "Checking enter_name and save_phone_dir\n",
        "{'Abc Def': 9840336105, 'Mno Pqr': 681990341, 'Ghi Jkl': 9869369319}\n",
        "9840336105 Abc Def\n",
        "9869369319 Ghi Jkl\n",
        "681990341 Mno Pqr\n",
        "\n"
       ]
      }
     ],
     "prompt_number": 6
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "def list_names(name) :\n",
      "    print \"Name                |Number\"\n",
      "    print \"-----------------------------------------\"\n",
      "    for e in phonedir :\n",
      "        if name in e :\n",
      "            print \"%19s |%d\" % (e, phonedir[e]) "
     ],
     "language": "python",
     "metadata": {},
     "outputs": [],
     "prompt_number": 7
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "if __name__ == '__main__' :\n",
      "    print \"Testing list_names\"\n",
      "    list_names('bc')\n",
      "    print 10*'-'\n",
      "    list_names(' ')\n",
      "    print 10*'-'\n",
      "    list_names('zx')"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "Testing list_names\n",
        "Name                |Number\n",
        "-----------------------------------------\n",
        "            Abc Def |9840336105\n",
        "----------\n",
        "Name                |Number\n",
        "-----------------------------------------\n",
        "            Abc Def |9840336105\n",
        "            Mno Pqr |681990341\n",
        "            Ghi Jkl |9869369319\n",
        "----------\n",
        "Name                |Number\n",
        "-----------------------------------------\n"
       ]
      }
     ],
     "prompt_number": 8
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "def delete_entry(name) :\n",
      "    dellist = []\n",
      "    for e in phonedir :\n",
      "        if name in e :\n",
      "            query_string = \"Delete %s(%d)? (y/n) \" % (e, phonedir[e])\n",
      "            ans = raw_input(query_string)\n",
      "            if ans == 'y' :\n",
      "                dellist.append(e)\n",
      "    for e in dellist :\n",
      "        del phonedir[e]\n",
      "    return None"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [],
     "prompt_number": 9
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "if __name__ == '__main__' :\n",
      "    print \"Testing delete_entry\"\n",
      "    delete_entry('bc')\n",
      "    print phonedir"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "Testing delete_entry\n"
       ]
      },
      {
       "name": "stdout",
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "Delete Abc Def(9840336105)? (y/n) y\n"
       ]
      },
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "{'Mno Pqr': 681990341, 'Ghi Jkl': 9869369319}\n"
       ]
      }
     ],
     "prompt_number": 10
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "def user_interface() :\n",
      "    exit = False\n",
      "    error = False\n",
      "    load_directory()\n",
      "    while not exit :\n",
      "        user_input = raw_input(\"Phone > \")\n",
      "        if user_input.strip() == 'exit' or user_input.strip() == 'quit' :\n",
      "            save_phone_dir()\n",
      "            exit = True\n",
      "        elif user_input.strip() == 'enter' or user_input.strip() == 'e' :\n",
      "            name =   raw_input(\"\\tName   : \")\n",
      "            number = raw_input(\"\\tNumber : \")\n",
      "            try :\n",
      "                no = float(number)\n",
      "            except ValueError :\n",
      "                print \"Something is wrong with the number.\"\n",
      "                error = True\n",
      "            if not error :\n",
      "                enter_name(name, no)\n",
      "            error = False\n",
      "        elif user_input.strip() == 'delete' or user_input.strip() == 'd' :\n",
      "            name = raw_input(\"\\tName : \")\n",
      "            delete_entry(name)\n",
      "        else :\n",
      "            list_names(user_input)\n",
      "        save_phone_dir()"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [],
     "prompt_number": 11
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "if __name__ == '__main__' :\n",
      "    print \"Testing user interface\"\n",
      "    user_interface()"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "Testing user interface\n"
       ]
      },
      {
       "name": "stdout",
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "Phone > \n"
       ]
      },
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "Name                |Number\n",
        "-----------------------------------------\n",
        "            Abc Def |9840336105\n",
        "            Mno Pqr |681990341\n",
        "            Ghi Jkl |9869369319\n"
       ]
      },
      {
       "name": "stdout",
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "Phone > d\n"
       ]
      },
      {
       "name": "stdout",
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "\tName : Mno\n"
       ]
      },
      {
       "name": "stdout",
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "Delete Mno Pqr(681990341)? (y/n) y\n"
       ]
      },
      {
       "name": "stdout",
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "Phone > quit\n"
       ]
      }
     ],
     "prompt_number": 12
    }
   ],
   "metadata": {}
  }
 ]
}