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  {
   "cells": [
    {
     "cell_type": "markdown",
     "metadata": {},
     "source": [
      "# Apply Operations Over Items In A List"
     ]
    },
    {
     "cell_type": "markdown",
     "metadata": {},
     "source": [
      "- **Author:** [Chris Albon](http://www.chrisalbon.com/), [@ChrisAlbon](https://twitter.com/chrisalbon)\n",
      "- **Date:** -\n",
      "- **Repo:** [Python 3 code snippets for data science](https://github.com/chrisalbon/code_py)\n",
      "- **Note:** Based on: Learning Python"
     ]
    },
    {
     "cell_type": "markdown",
     "metadata": {},
     "source": [
      "## Method 1: map()"
     ]
    },
    {
     "cell_type": "markdown",
     "metadata": {},
     "source": [
      "### Create a list of casualties from battles"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "battleDeaths = [482, 93, 392, 920, 813, 199, 374, 237, 244]"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [],
     "prompt_number": 20
    },
    {
     "cell_type": "markdown",
     "metadata": {},
     "source": [
      "### Create a function that updates all battle deaths by adding 100"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "def updated(x): return x + 100"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [],
     "prompt_number": 21
    },
    {
     "cell_type": "markdown",
     "metadata": {},
     "source": [
      "### Create a list that applies updated() to all elements of battleDeaths"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "list(map(updated, battleDeaths))"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "metadata": {},
       "output_type": "pyout",
       "prompt_number": 22,
       "text": [
        "[582, 193, 492, 1020, 913, 299, 474, 337, 344]"
       ]
      }
     ],
     "prompt_number": 22
    },
    {
     "cell_type": "markdown",
     "metadata": {},
     "source": [
      "## Method 2: for x in y"
     ]
    },
    {
     "cell_type": "markdown",
     "metadata": {},
     "source": [
      "### Create a list of deaths"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "casualties = [482, 93, 392, 920, 813, 199, 374, 237, 244]"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [],
     "prompt_number": 24
    },
    {
     "cell_type": "markdown",
     "metadata": {},
     "source": [
      "### Create a variable where we will put the updated casualty numbers"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "casualtiesUpdated = []"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [],
     "prompt_number": 25
    },
    {
     "cell_type": "markdown",
     "metadata": {},
     "source": [
      "### Create a function that for each item in casualties, adds 10"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "for x in casualties:\n",
      "    casualtiesUpdated.append(x + 100)"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [],
     "prompt_number": 26
    },
    {
     "cell_type": "markdown",
     "metadata": {},
     "source": [
      "### View casualties variables"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "casualtiesUpdated"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "metadata": {},
       "output_type": "pyout",
       "prompt_number": 27,
       "text": [
        "[582, 193, 492, 1020, 913, 299, 474, 337, 344]"
       ]
      }
     ],
     "prompt_number": 27
    },
    {
     "cell_type": "markdown",
     "metadata": {},
     "source": [
      "### Method 3: lambda functions"
     ]
    },
    {
     "cell_type": "markdown",
     "metadata": {},
     "source": [
      "### Map the lambda function x() over casualties"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "list(map((lambda x: x + 100), casualties))"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "metadata": {},
       "output_type": "pyout",
       "prompt_number": 29,
       "text": [
        "[582, 193, 492, 1020, 913, 299, 474, 337, 344]"
       ]
      }
     ],
     "prompt_number": 29
    }
   ],
   "metadata": {}
  }
 ]
}