09_Set a Datetime Column as the Index.ipynb

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 "cells": [
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   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# 09_Set a Datetime Column as the Index"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "import pandas as pd"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Load the example *timeseries_daily.csv* dataset:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [
    {
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       "  <thead>\n",
       "    <tr style=\"text-align: right;\">\n",
       "      <th></th>\n",
       "      <th>Date</th>\n",
       "      <th>feature_1</th>\n",
       "      <th>feature_2</th>\n",
       "      <th>feature_3</th>\n",
       "      <th>feature_4</th>\n",
       "      <th>categorical_feature</th>\n",
       "      <th>weekday</th>\n",
       "    </tr>\n",
       "  </thead>\n",
       "  <tbody>\n",
       "    <tr>\n",
       "      <th>0</th>\n",
       "      <td>01/02/2017</td>\n",
       "      <td>0</td>\n",
       "      <td>0</td>\n",
       "      <td>37</td>\n",
       "      <td>0</td>\n",
       "      <td>foo</td>\n",
       "      <td>Wednesday</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1</th>\n",
       "      <td>02/02/2017</td>\n",
       "      <td>0</td>\n",
       "      <td>0</td>\n",
       "      <td>168</td>\n",
       "      <td>0</td>\n",
       "      <td>foo</td>\n",
       "      <td>Thursday</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2</th>\n",
       "      <td>03/02/2017</td>\n",
       "      <td>0</td>\n",
       "      <td>0</td>\n",
       "      <td>157</td>\n",
       "      <td>0</td>\n",
       "      <td>other</td>\n",
       "      <td>Friday</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>3</th>\n",
       "      <td>04/02/2017</td>\n",
       "      <td>0</td>\n",
       "      <td>0</td>\n",
       "      <td>720</td>\n",
       "      <td>0</td>\n",
       "      <td>other</td>\n",
       "      <td>Saturday</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>4</th>\n",
       "      <td>05/02/2017</td>\n",
       "      <td>0</td>\n",
       "      <td>0</td>\n",
       "      <td>721</td>\n",
       "      <td>0</td>\n",
       "      <td>bar</td>\n",
       "      <td>Sunday</td>\n",
       "    </tr>\n",
       "  </tbody>\n",
       "</table>\n",
       "</div>"
      ],
      "text/plain": [
       "         Date  feature_1  feature_2  feature_3  feature_4 categorical_feature  \\\n",
       "0  01/02/2017          0          0         37          0                 foo   \n",
       "1  02/02/2017          0          0        168          0                 foo   \n",
       "2  03/02/2017          0          0        157          0               other   \n",
       "3  04/02/2017          0          0        720          0               other   \n",
       "4  05/02/2017          0          0        721          0                 bar   \n",
       "\n",
       "     weekday  \n",
       "0  Wednesday  \n",
       "1   Thursday  \n",
       "2     Friday  \n",
       "3   Saturday  \n",
       "4     Sunday  "
      ]
     },
     "execution_count": 2,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "df = pd.read_csv(\"./data_etc/timeseries_daily.csv\")\n",
    "df.head()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Create a proper datetime column:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [
    {
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       "  <thead>\n",
       "    <tr style=\"text-align: right;\">\n",
       "      <th></th>\n",
       "      <th>Date</th>\n",
       "      <th>feature_1</th>\n",
       "      <th>feature_2</th>\n",
       "      <th>feature_3</th>\n",
       "      <th>feature_4</th>\n",
       "      <th>categorical_feature</th>\n",
       "      <th>weekday</th>\n",
       "      <th>datetime</th>\n",
       "    </tr>\n",
       "  </thead>\n",
       "  <tbody>\n",
       "    <tr>\n",
       "      <th>0</th>\n",
       "      <td>01/02/2017</td>\n",
       "      <td>0</td>\n",
       "      <td>0</td>\n",
       "      <td>37</td>\n",
       "      <td>0</td>\n",
       "      <td>foo</td>\n",
       "      <td>Wednesday</td>\n",
       "      <td>2017-02-01</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1</th>\n",
       "      <td>02/02/2017</td>\n",
       "      <td>0</td>\n",
       "      <td>0</td>\n",
       "      <td>168</td>\n",
       "      <td>0</td>\n",
       "      <td>foo</td>\n",
       "      <td>Thursday</td>\n",
       "      <td>2017-02-02</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2</th>\n",
       "      <td>03/02/2017</td>\n",
       "      <td>0</td>\n",
       "      <td>0</td>\n",
       "      <td>157</td>\n",
       "      <td>0</td>\n",
       "      <td>other</td>\n",
       "      <td>Friday</td>\n",
       "      <td>2017-02-03</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>3</th>\n",
       "      <td>04/02/2017</td>\n",
       "      <td>0</td>\n",
       "      <td>0</td>\n",
       "      <td>720</td>\n",
       "      <td>0</td>\n",
       "      <td>other</td>\n",
       "      <td>Saturday</td>\n",
       "      <td>2017-02-04</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>4</th>\n",
       "      <td>05/02/2017</td>\n",
       "      <td>0</td>\n",
       "      <td>0</td>\n",
       "      <td>721</td>\n",
       "      <td>0</td>\n",
       "      <td>bar</td>\n",
       "      <td>Sunday</td>\n",
       "      <td>2017-02-05</td>\n",
       "    </tr>\n",
       "  </tbody>\n",
       "</table>\n",
       "</div>"
      ],
      "text/plain": [
       "         Date  feature_1  feature_2  feature_3  feature_4 categorical_feature  \\\n",
       "0  01/02/2017          0          0         37          0                 foo   \n",
       "1  02/02/2017          0          0        168          0                 foo   \n",
       "2  03/02/2017          0          0        157          0               other   \n",
       "3  04/02/2017          0          0        720          0               other   \n",
       "4  05/02/2017          0          0        721          0                 bar   \n",
       "\n",
       "     weekday   datetime  \n",
       "0  Wednesday 2017-02-01  \n",
       "1   Thursday 2017-02-02  \n",
       "2     Friday 2017-02-03  \n",
       "3   Saturday 2017-02-04  \n",
       "4     Sunday 2017-02-05  "
      ]
     },
     "execution_count": 3,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "# Create a proper datetime column\n",
    "df[\"datetime\"] = pd.to_datetime(df[\"Date\"], dayfirst=True)\n",
    "\n",
    "df.head()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Set the column as the DataFrame Index:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {},
   "outputs": [
    {
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       "  <thead>\n",
       "    <tr style=\"text-align: right;\">\n",
       "      <th></th>\n",
       "      <th>Date</th>\n",
       "      <th>feature_1</th>\n",
       "      <th>feature_2</th>\n",
       "      <th>feature_3</th>\n",
       "      <th>feature_4</th>\n",
       "      <th>categorical_feature</th>\n",
       "      <th>weekday</th>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>datetime</th>\n",
       "      <th></th>\n",
       "      <th></th>\n",
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       "  <tbody>\n",
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       "      <th>2017-02-01</th>\n",
       "      <td>01/02/2017</td>\n",
       "      <td>0</td>\n",
       "      <td>0</td>\n",
       "      <td>37</td>\n",
       "      <td>0</td>\n",
       "      <td>foo</td>\n",
       "      <td>Wednesday</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2017-02-02</th>\n",
       "      <td>02/02/2017</td>\n",
       "      <td>0</td>\n",
       "      <td>0</td>\n",
       "      <td>168</td>\n",
       "      <td>0</td>\n",
       "      <td>foo</td>\n",
       "      <td>Thursday</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2017-02-03</th>\n",
       "      <td>03/02/2017</td>\n",
       "      <td>0</td>\n",
       "      <td>0</td>\n",
       "      <td>157</td>\n",
       "      <td>0</td>\n",
       "      <td>other</td>\n",
       "      <td>Friday</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2017-02-04</th>\n",
       "      <td>04/02/2017</td>\n",
       "      <td>0</td>\n",
       "      <td>0</td>\n",
       "      <td>720</td>\n",
       "      <td>0</td>\n",
       "      <td>other</td>\n",
       "      <td>Saturday</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2017-02-05</th>\n",
       "      <td>05/02/2017</td>\n",
       "      <td>0</td>\n",
       "      <td>0</td>\n",
       "      <td>721</td>\n",
       "      <td>0</td>\n",
       "      <td>bar</td>\n",
       "      <td>Sunday</td>\n",
       "    </tr>\n",
       "  </tbody>\n",
       "</table>\n",
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      ],
      "text/plain": [
       "                  Date  feature_1  feature_2  feature_3  feature_4  \\\n",
       "datetime                                                             \n",
       "2017-02-01  01/02/2017          0          0         37          0   \n",
       "2017-02-02  02/02/2017          0          0        168          0   \n",
       "2017-02-03  03/02/2017          0          0        157          0   \n",
       "2017-02-04  04/02/2017          0          0        720          0   \n",
       "2017-02-05  05/02/2017          0          0        721          0   \n",
       "\n",
       "           categorical_feature    weekday  \n",
       "datetime                                   \n",
       "2017-02-01                 foo  Wednesday  \n",
       "2017-02-02                 foo   Thursday  \n",
       "2017-02-03               other     Friday  \n",
       "2017-02-04               other   Saturday  \n",
       "2017-02-05                 bar     Sunday  "
      ]
     },
     "execution_count": 4,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "df.set_index([\"datetime\"], inplace=True)\n",
    "df.head()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "collapsed": true
   },
   "source": [
    "Note the <code>inplace=True<code> flag, which means that the original DataFrame is changed. If <code>inplace=False</code> (the default) is used instead, then a new DataFrame will be returned and the original remains unchanged."
   ]
  }
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