Lec 24 - Index Hierarchy.ipynb

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  {
   "cells": [
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "import numpy as np\n",
      "from pandas import Series,DataFrame\n",
      "import pandas as pd\n",
      "\n",
      "from numpy.random import randn"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [],
     "prompt_number": 1
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "#Now we'll learn about Index Hierarchy\n",
      "\n",
      "#pandas allows you to have multiple index levels, which is very clear with this example:\n",
      "\n",
      "ser = Series(np.random.randn(6),index=[[1,1,1,2,2,2],['a','b','c','a','b','c']])"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [],
     "prompt_number": 11
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "#Show Series with multiple index levels\n",
      "ser"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "metadata": {},
       "output_type": "pyout",
       "prompt_number": 12,
       "text": [
        "1  a   -1.337299\n",
        "   b   -0.690616\n",
        "   c    1.792962\n",
        "2  a    0.457808\n",
        "   b    0.891199\n",
        "   c   -1.366387\n",
        "dtype: float64"
       ]
      }
     ],
     "prompt_number": 12
    },
    {
     "cell_type": "code",
     "collapsed": true,
     "input": [
      "# We can check the multiple levels\n",
      "ser.index"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "metadata": {},
       "output_type": "pyout",
       "prompt_number": 14,
       "text": [
        "MultiIndex(levels=[[1, 2], [u'a', u'b', u'c']],\n",
        "           labels=[[0, 0, 0, 1, 1, 1], [0, 1, 2, 0, 1, 2]])"
       ]
      }
     ],
     "prompt_number": 14
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "#Now we can sleect specific subsets\n",
      "ser[1]"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "metadata": {},
       "output_type": "pyout",
       "prompt_number": 15,
       "text": [
        "a   -1.337299\n",
        "b   -0.690616\n",
        "c    1.792962\n",
        "dtype: float64"
       ]
      }
     ],
     "prompt_number": 15
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "# We can also select from an internal index level\n",
      "ser[:,'a']"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "metadata": {},
       "output_type": "pyout",
       "prompt_number": 16,
       "text": [
        "1   -1.337299\n",
        "2    0.457808\n",
        "dtype: float64"
       ]
      }
     ],
     "prompt_number": 16
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "# We can also create Data Frames from Series with multiple levels\n",
      "dframe = ser.unstack()\n",
      "\n",
      "#Show\n",
      "dframe"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "html": [
        "<div style=\"max-height:1000px;max-width:1500px;overflow:auto;\">\n",
        "<table border=\"1\" class=\"dataframe\">\n",
        "  <thead>\n",
        "    <tr style=\"text-align: right;\">\n",
        "      <th></th>\n",
        "      <th>a</th>\n",
        "      <th>b</th>\n",
        "      <th>c</th>\n",
        "    </tr>\n",
        "  </thead>\n",
        "  <tbody>\n",
        "    <tr>\n",
        "      <th>1</th>\n",
        "      <td>-1.337299</td>\n",
        "      <td>-0.690616</td>\n",
        "      <td> 1.792962</td>\n",
        "    </tr>\n",
        "    <tr>\n",
        "      <th>2</th>\n",
        "      <td> 0.457808</td>\n",
        "      <td> 0.891199</td>\n",
        "      <td>-1.366387</td>\n",
        "    </tr>\n",
        "  </tbody>\n",
        "</table>\n",
        "</div>"
       ],
       "metadata": {},
       "output_type": "pyout",
       "prompt_number": 19,
       "text": [
        "          a         b         c\n",
        "1 -1.337299 -0.690616  1.792962\n",
        "2  0.457808  0.891199 -1.366387"
       ]
      }
     ],
     "prompt_number": 19
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "#Can also reverse\n",
      "dframe.unstack()"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "metadata": {},
       "output_type": "pyout",
       "prompt_number": 20,
       "text": [
        "a  1   -1.337299\n",
        "   2    0.457808\n",
        "b  1   -0.690616\n",
        "   2    0.891199\n",
        "c  1    1.792962\n",
        "   2   -1.366387\n",
        "dtype: float64"
       ]
      }
     ],
     "prompt_number": 20
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "# We can also apply multiple level indexing to DataFrames\n",
      "dframe2 = DataFrame(np.arange(16).reshape(4,4),\n",
      "                    index=[['a','a','b','b'],[1,2,1,2]],\n",
      "                    columns=[['NY','NY','LA','SF'],['cold','hot','hot','cold']])\n",
      "                                                   \n",
      "dframe2                                                "
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "html": [
        "<div style=\"max-height:1000px;max-width:1500px;overflow:auto;\">\n",
        "<table border=\"1\" class=\"dataframe\">\n",
        "  <thead>\n",
        "    <tr>\n",
        "      <th></th>\n",
        "      <th></th>\n",
        "      <th colspan=\"2\" halign=\"left\">NY</th>\n",
        "      <th>LA</th>\n",
        "      <th>SF</th>\n",
        "    </tr>\n",
        "    <tr>\n",
        "      <th></th>\n",
        "      <th></th>\n",
        "      <th>cold</th>\n",
        "      <th>hot</th>\n",
        "      <th>hot</th>\n",
        "      <th>cold</th>\n",
        "    </tr>\n",
        "  </thead>\n",
        "  <tbody>\n",
        "    <tr>\n",
        "      <th rowspan=\"2\" valign=\"top\">a</th>\n",
        "      <th>1</th>\n",
        "      <td>  0</td>\n",
        "      <td>  1</td>\n",
        "      <td>  2</td>\n",
        "      <td>  3</td>\n",
        "    </tr>\n",
        "    <tr>\n",
        "      <th>2</th>\n",
        "      <td>  4</td>\n",
        "      <td>  5</td>\n",
        "      <td>  6</td>\n",
        "      <td>  7</td>\n",
        "    </tr>\n",
        "    <tr>\n",
        "      <th rowspan=\"2\" valign=\"top\">b</th>\n",
        "      <th>1</th>\n",
        "      <td>  8</td>\n",
        "      <td>  9</td>\n",
        "      <td> 10</td>\n",
        "      <td> 11</td>\n",
        "    </tr>\n",
        "    <tr>\n",
        "      <th>2</th>\n",
        "      <td> 12</td>\n",
        "      <td> 13</td>\n",
        "      <td> 14</td>\n",
        "      <td> 15</td>\n",
        "    </tr>\n",
        "  </tbody>\n",
        "</table>\n",
        "</div>"
       ],
       "metadata": {},
       "output_type": "pyout",
       "prompt_number": 28,
       "text": [
        "      NY      LA   SF\n",
        "    cold hot hot cold\n",
        "a 1    0   1   2    3\n",
        "  2    4   5   6    7\n",
        "b 1    8   9  10   11\n",
        "  2   12  13  14   15"
       ]
      }
     ],
     "prompt_number": 28
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "# We can also give these index levels names\n",
      "\n",
      "#Name the index levels\n",
      "dframe2.index.names = ['INDEX_1','INDEX_2']\n",
      "\n",
      "#Name the column levels\n",
      "dframe2.columns.names = ['Cities','Temp']\n",
      "\n",
      "dframe2"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "html": [
        "<div style=\"max-height:1000px;max-width:1500px;overflow:auto;\">\n",
        "<table border=\"1\" class=\"dataframe\">\n",
        "  <thead>\n",
        "    <tr>\n",
        "      <th></th>\n",
        "      <th>Cities</th>\n",
        "      <th colspan=\"2\" halign=\"left\">NY</th>\n",
        "      <th>LA</th>\n",
        "      <th>SF</th>\n",
        "    </tr>\n",
        "    <tr>\n",
        "      <th></th>\n",
        "      <th>Temp</th>\n",
        "      <th>cold</th>\n",
        "      <th>hot</th>\n",
        "      <th>hot</th>\n",
        "      <th>cold</th>\n",
        "    </tr>\n",
        "    <tr>\n",
        "      <th>INDEX_1</th>\n",
        "      <th>INDEX_2</th>\n",
        "      <th></th>\n",
        "      <th></th>\n",
        "      <th></th>\n",
        "      <th></th>\n",
        "    </tr>\n",
        "  </thead>\n",
        "  <tbody>\n",
        "    <tr>\n",
        "      <th rowspan=\"2\" valign=\"top\">a</th>\n",
        "      <th>1</th>\n",
        "      <td>  0</td>\n",
        "      <td>  1</td>\n",
        "      <td>  2</td>\n",
        "      <td>  3</td>\n",
        "    </tr>\n",
        "    <tr>\n",
        "      <th>2</th>\n",
        "      <td>  4</td>\n",
        "      <td>  5</td>\n",
        "      <td>  6</td>\n",
        "      <td>  7</td>\n",
        "    </tr>\n",
        "    <tr>\n",
        "      <th rowspan=\"2\" valign=\"top\">b</th>\n",
        "      <th>1</th>\n",
        "      <td>  8</td>\n",
        "      <td>  9</td>\n",
        "      <td> 10</td>\n",
        "      <td> 11</td>\n",
        "    </tr>\n",
        "    <tr>\n",
        "      <th>2</th>\n",
        "      <td> 12</td>\n",
        "      <td> 13</td>\n",
        "      <td> 14</td>\n",
        "      <td> 15</td>\n",
        "    </tr>\n",
        "  </tbody>\n",
        "</table>\n",
        "</div>"
       ],
       "metadata": {},
       "output_type": "pyout",
       "prompt_number": 31,
       "text": [
        "Cities            NY      LA   SF\n",
        "Temp            cold hot hot cold\n",
        "INDEX_1 INDEX_2                  \n",
        "a       1          0   1   2    3\n",
        "        2          4   5   6    7\n",
        "b       1          8   9  10   11\n",
        "        2         12  13  14   15"
       ]
      }
     ],
     "prompt_number": 31
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "# We can also interchange level orders (note the axis=1 for columns)\n",
      "dframe2.swaplevel('Cities','Temp',axis=1)"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "html": [
        "<div style=\"max-height:1000px;max-width:1500px;overflow:auto;\">\n",
        "<table border=\"1\" class=\"dataframe\">\n",
        "  <thead>\n",
        "    <tr>\n",
        "      <th></th>\n",
        "      <th>Temp</th>\n",
        "      <th>cold</th>\n",
        "      <th colspan=\"2\" halign=\"left\">hot</th>\n",
        "      <th>cold</th>\n",
        "    </tr>\n",
        "    <tr>\n",
        "      <th></th>\n",
        "      <th>Cities</th>\n",
        "      <th>NY</th>\n",
        "      <th>NY</th>\n",
        "      <th>LA</th>\n",
        "      <th>SF</th>\n",
        "    </tr>\n",
        "    <tr>\n",
        "      <th>INDEX_1</th>\n",
        "      <th>INDEX_2</th>\n",
        "      <th></th>\n",
        "      <th></th>\n",
        "      <th></th>\n",
        "      <th></th>\n",
        "    </tr>\n",
        "  </thead>\n",
        "  <tbody>\n",
        "    <tr>\n",
        "      <th rowspan=\"2\" valign=\"top\">a</th>\n",
        "      <th>1</th>\n",
        "      <td>  0</td>\n",
        "      <td>  1</td>\n",
        "      <td>  2</td>\n",
        "      <td>  3</td>\n",
        "    </tr>\n",
        "    <tr>\n",
        "      <th>2</th>\n",
        "      <td>  4</td>\n",
        "      <td>  5</td>\n",
        "      <td>  6</td>\n",
        "      <td>  7</td>\n",
        "    </tr>\n",
        "    <tr>\n",
        "      <th rowspan=\"2\" valign=\"top\">b</th>\n",
        "      <th>1</th>\n",
        "      <td>  8</td>\n",
        "      <td>  9</td>\n",
        "      <td> 10</td>\n",
        "      <td> 11</td>\n",
        "    </tr>\n",
        "    <tr>\n",
        "      <th>2</th>\n",
        "      <td> 12</td>\n",
        "      <td> 13</td>\n",
        "      <td> 14</td>\n",
        "      <td> 15</td>\n",
        "    </tr>\n",
        "  </tbody>\n",
        "</table>\n",
        "</div>"
       ],
       "metadata": {},
       "output_type": "pyout",
       "prompt_number": 33,
       "text": [
        "Temp            cold hot     cold\n",
        "Cities            NY  NY  LA   SF\n",
        "INDEX_1 INDEX_2                  \n",
        "a       1          0   1   2    3\n",
        "        2          4   5   6    7\n",
        "b       1          8   9  10   11\n",
        "        2         12  13  14   15"
       ]
      }
     ],
     "prompt_number": 33
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "#We can also sort levels\n",
      "dframe2.sortlevel(1)"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "html": [
        "<div style=\"max-height:1000px;max-width:1500px;overflow:auto;\">\n",
        "<table border=\"1\" class=\"dataframe\">\n",
        "  <thead>\n",
        "    <tr>\n",
        "      <th></th>\n",
        "      <th>Cities</th>\n",
        "      <th colspan=\"2\" halign=\"left\">NY</th>\n",
        "      <th>LA</th>\n",
        "      <th>SF</th>\n",
        "    </tr>\n",
        "    <tr>\n",
        "      <th></th>\n",
        "      <th>Temp</th>\n",
        "      <th>cold</th>\n",
        "      <th>hot</th>\n",
        "      <th>hot</th>\n",
        "      <th>cold</th>\n",
        "    </tr>\n",
        "    <tr>\n",
        "      <th>INDEX_1</th>\n",
        "      <th>INDEX_2</th>\n",
        "      <th></th>\n",
        "      <th></th>\n",
        "      <th></th>\n",
        "      <th></th>\n",
        "    </tr>\n",
        "  </thead>\n",
        "  <tbody>\n",
        "    <tr>\n",
        "      <th>a</th>\n",
        "      <th>1</th>\n",
        "      <td>  0</td>\n",
        "      <td>  1</td>\n",
        "      <td>  2</td>\n",
        "      <td>  3</td>\n",
        "    </tr>\n",
        "    <tr>\n",
        "      <th>b</th>\n",
        "      <th>1</th>\n",
        "      <td>  8</td>\n",
        "      <td>  9</td>\n",
        "      <td> 10</td>\n",
        "      <td> 11</td>\n",
        "    </tr>\n",
        "    <tr>\n",
        "      <th>a</th>\n",
        "      <th>2</th>\n",
        "      <td>  4</td>\n",
        "      <td>  5</td>\n",
        "      <td>  6</td>\n",
        "      <td>  7</td>\n",
        "    </tr>\n",
        "    <tr>\n",
        "      <th>b</th>\n",
        "      <th>2</th>\n",
        "      <td> 12</td>\n",
        "      <td> 13</td>\n",
        "      <td> 14</td>\n",
        "      <td> 15</td>\n",
        "    </tr>\n",
        "  </tbody>\n",
        "</table>\n",
        "</div>"
       ],
       "metadata": {},
       "output_type": "pyout",
       "prompt_number": 34,
       "text": [
        "Cities            NY      LA   SF\n",
        "Temp            cold hot hot cold\n",
        "INDEX_1 INDEX_2                  \n",
        "a       1          0   1   2    3\n",
        "b       1          8   9  10   11\n",
        "a       2          4   5   6    7\n",
        "b       2         12  13  14   15"
       ]
      }
     ],
     "prompt_number": 34
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "#Note the change in sorting, now the Dframe index is sorted by the INDEX_2"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [],
     "prompt_number": 35
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "#We can also perform operations on particular levels\n",
      "dframe2.sum(level='Temp',axis=1)"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "html": [
        "<div style=\"max-height:1000px;max-width:1500px;overflow:auto;\">\n",
        "<table border=\"1\" class=\"dataframe\">\n",
        "  <thead>\n",
        "    <tr style=\"text-align: right;\">\n",
        "      <th></th>\n",
        "      <th>Temp</th>\n",
        "      <th>cold</th>\n",
        "      <th>hot</th>\n",
        "    </tr>\n",
        "    <tr>\n",
        "      <th>INDEX_1</th>\n",
        "      <th>INDEX_2</th>\n",
        "      <th></th>\n",
        "      <th></th>\n",
        "    </tr>\n",
        "  </thead>\n",
        "  <tbody>\n",
        "    <tr>\n",
        "      <th rowspan=\"2\" valign=\"top\">a</th>\n",
        "      <th>1</th>\n",
        "      <td>  3</td>\n",
        "      <td>  3</td>\n",
        "    </tr>\n",
        "    <tr>\n",
        "      <th>2</th>\n",
        "      <td> 11</td>\n",
        "      <td> 11</td>\n",
        "    </tr>\n",
        "    <tr>\n",
        "      <th rowspan=\"2\" valign=\"top\">b</th>\n",
        "      <th>1</th>\n",
        "      <td> 19</td>\n",
        "      <td> 19</td>\n",
        "    </tr>\n",
        "    <tr>\n",
        "      <th>2</th>\n",
        "      <td> 27</td>\n",
        "      <td> 27</td>\n",
        "    </tr>\n",
        "  </tbody>\n",
        "</table>\n",
        "</div>"
       ],
       "metadata": {},
       "output_type": "pyout",
       "prompt_number": 37,
       "text": [
        "Temp             cold  hot\n",
        "INDEX_1 INDEX_2           \n",
        "a       1           3    3\n",
        "        2          11   11\n",
        "b       1          19   19\n",
        "        2          27   27"
       ]
      }
     ],
     "prompt_number": 37
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "#Thats the end of this section! Next up, Section 5: Working with Data Part 1 !!!"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [],
     "prompt_number": 38
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [],
     "language": "python",
     "metadata": {},
     "outputs": []
    }
   ],
   "metadata": {}
  }
 ]
}