CH1/templates/7_0_pandas_indexing_selection.ipynb

{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Библиотека Pandas"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Data Frame"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "import pandas as pd"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "#создание DataFrame с помощью чтения данных из файла\n",
    "frame = pd.read_csv('data_sample_example.tsv', header=0, sep='\\t')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div>\n",
       "<table border=\"1\" class=\"dataframe\">\n",
       "  <thead>\n",
       "    <tr style=\"text-align: right;\">\n",
       "      <th></th>\n",
       "      <th>Name</th>\n",
       "      <th>Birth</th>\n",
       "      <th>City</th>\n",
       "      <th>Position</th>\n",
       "    </tr>\n",
       "  </thead>\n",
       "  <tbody>\n",
       "    <tr>\n",
       "      <th>0</th>\n",
       "      <td>Иванов А.А.</td>\n",
       "      <td>22.03.1980</td>\n",
       "      <td>Москва</td>\n",
       "      <td>NaN</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1</th>\n",
       "      <td>Сорокин И.В.</td>\n",
       "      <td>07.08.1965</td>\n",
       "      <td>Волгоград</td>\n",
       "      <td>инженер</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2</th>\n",
       "      <td>Белов М.М.</td>\n",
       "      <td>13.02.1980</td>\n",
       "      <td>Ростов</td>\n",
       "      <td>менеджер</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>3</th>\n",
       "      <td>Мельникова Д.С.</td>\n",
       "      <td>15.04.1985</td>\n",
       "      <td>Ростов</td>\n",
       "      <td>NaN</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>4</th>\n",
       "      <td>Рыбина Е.П.</td>\n",
       "      <td>19.11.1985</td>\n",
       "      <td>Москва</td>\n",
       "      <td>инженер</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>5</th>\n",
       "      <td>Костров С.О.</td>\n",
       "      <td>31.05.1985</td>\n",
       "      <td>Москва</td>\n",
       "      <td>стажер</td>\n",
       "    </tr>\n",
       "  </tbody>\n",
       "</table>\n",
       "</div>"
      ],
      "text/plain": [
       "              Name       Birth       City  Position\n",
       "0      Иванов А.А.  22.03.1980     Москва       NaN\n",
       "1     Сорокин И.В.  07.08.1965  Волгоград   инженер\n",
       "2       Белов М.М.  13.02.1980     Ростов  менеджер\n",
       "3  Мельникова Д.С.  15.04.1985     Ростов       NaN\n",
       "4      Рыбина Е.П.  19.11.1985     Москва   инженер\n",
       "5     Костров С.О.  31.05.1985     Москва    стажер"
      ]
     },
     "execution_count": 4,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "frame"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "Name                object\n",
       "Birth       datetime64[ns]\n",
       "City                object\n",
       "Position            object\n",
       "dtype: object"
      ]
     },
     "execution_count": 8,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "frame.dtypes"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "#изменение типа столбца с помощью функции apply\n",
    "frame.Birth = frame.Birth.apply(pd.to_datetime)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div>\n",
       "<table border=\"1\" class=\"dataframe\">\n",
       "  <thead>\n",
       "    <tr style=\"text-align: right;\">\n",
       "      <th></th>\n",
       "      <th>Name</th>\n",
       "      <th>Birth</th>\n",
       "      <th>City</th>\n",
       "      <th>Position</th>\n",
       "    </tr>\n",
       "  </thead>\n",
       "  <tbody>\n",
       "    <tr>\n",
       "      <th>0</th>\n",
       "      <td>Иванов А.А.</td>\n",
       "      <td>1980-03-22</td>\n",
       "      <td>Москва</td>\n",
       "      <td>NaN</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1</th>\n",
       "      <td>Сорокин И.В.</td>\n",
       "      <td>1965-07-08</td>\n",
       "      <td>Волгоград</td>\n",
       "      <td>инженер</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2</th>\n",
       "      <td>Белов М.М.</td>\n",
       "      <td>1980-02-13</td>\n",
       "      <td>Ростов</td>\n",
       "      <td>менеджер</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>3</th>\n",
       "      <td>Мельникова Д.С.</td>\n",
       "      <td>1985-04-15</td>\n",
       "      <td>Ростов</td>\n",
       "      <td>NaN</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>4</th>\n",
       "      <td>Рыбина Е.П.</td>\n",
       "      <td>1985-11-19</td>\n",
       "      <td>Москва</td>\n",
       "      <td>инженер</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>5</th>\n",
       "      <td>Костров С.О.</td>\n",
       "      <td>1985-05-31</td>\n",
       "      <td>Москва</td>\n",
       "      <td>стажер</td>\n",
       "    </tr>\n",
       "  </tbody>\n",
       "</table>\n",
       "</div>"
      ],
      "text/plain": [
       "              Name      Birth       City  Position\n",
       "0      Иванов А.А. 1980-03-22     Москва       NaN\n",
       "1     Сорокин И.В. 1965-07-08  Волгоград   инженер\n",
       "2       Белов М.М. 1980-02-13     Ростов  менеджер\n",
       "3  Мельникова Д.С. 1985-04-15     Ростов       NaN\n",
       "4      Рыбина Е.П. 1985-11-19     Москва   инженер\n",
       "5     Костров С.О. 1985-05-31     Москва    стажер"
      ]
     },
     "execution_count": 7,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "frame"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "frame.dtypes"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 10,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "<class 'pandas.core.frame.DataFrame'>\n",
      "Int64Index: 6 entries, 0 to 5\n",
      "Data columns (total 4 columns):\n",
      "Name        6 non-null object\n",
      "Birth       6 non-null datetime64[ns]\n",
      "City        6 non-null object\n",
      "Position    4 non-null object\n",
      "dtypes: datetime64[ns](1), object(3)\n",
      "memory usage: 240.0+ bytes\n"
     ]
    }
   ],
   "source": [
    "frame.info()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 11,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div>\n",
       "<table border=\"1\" class=\"dataframe\">\n",
       "  <thead>\n",
       "    <tr style=\"text-align: right;\">\n",
       "      <th></th>\n",
       "      <th>Name</th>\n",
       "      <th>Birth</th>\n",
       "      <th>City</th>\n",
       "      <th>Position</th>\n",
       "    </tr>\n",
       "  </thead>\n",
       "  <tbody>\n",
       "    <tr>\n",
       "      <th>0</th>\n",
       "      <td>Иванов А.А.</td>\n",
       "      <td>1980-03-22</td>\n",
       "      <td>Москва</td>\n",
       "      <td>разнорабочий</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1</th>\n",
       "      <td>Сорокин И.В.</td>\n",
       "      <td>1965-07-08</td>\n",
       "      <td>Волгоград</td>\n",
       "      <td>инженер</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2</th>\n",
       "      <td>Белов М.М.</td>\n",
       "      <td>1980-02-13</td>\n",
       "      <td>Ростов</td>\n",
       "      <td>менеджер</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>3</th>\n",
       "      <td>Мельникова Д.С.</td>\n",
       "      <td>1985-04-15</td>\n",
       "      <td>Ростов</td>\n",
       "      <td>разнорабочий</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>4</th>\n",
       "      <td>Рыбина Е.П.</td>\n",
       "      <td>1985-11-19</td>\n",
       "      <td>Москва</td>\n",
       "      <td>инженер</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>5</th>\n",
       "      <td>Костров С.О.</td>\n",
       "      <td>1985-05-31</td>\n",
       "      <td>Москва</td>\n",
       "      <td>стажер</td>\n",
       "    </tr>\n",
       "  </tbody>\n",
       "</table>\n",
       "</div>"
      ],
      "text/plain": [
       "              Name      Birth       City      Position\n",
       "0      Иванов А.А. 1980-03-22     Москва  разнорабочий\n",
       "1     Сорокин И.В. 1965-07-08  Волгоград       инженер\n",
       "2       Белов М.М. 1980-02-13     Ростов      менеджер\n",
       "3  Мельникова Д.С. 1985-04-15     Ростов  разнорабочий\n",
       "4      Рыбина Е.П. 1985-11-19     Москва       инженер\n",
       "5     Костров С.О. 1985-05-31     Москва        стажер"
      ]
     },
     "execution_count": 11,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "#заполнение пропущенных значений с помощью метода fillna\n",
    "frame.fillna('разнорабочий')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 12,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "#заполнение пропущенных значений с помощью метода fillna (inplace)\n",
    "frame.fillna('разнорабочий', inplace=True)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "frame"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "frame.Position"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "frame[['Position']]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "frame[['Name', 'Position']]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "frame[:3] #выбираем первые три записи"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "frame[-3:] #выбираем три послдение записи"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "frame.loc[[0,1,2], [\"Name\", \"City\"]] #работает на основе имен"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "frame.iloc[[1,3,5], [0,1]] #работает на основе позиций"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "frame.ix[[0,1,2], [\"Name\", \"City\"]]  #поддерживает и имена и позиции (пример с именами)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "frame.ix[[0,1,2], [0,1]] #поддерживает и имена и позиции (пример с позициями)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "#выбираем строки, которые удовлетворяют условию frame.Birth >= pd.datetime(1985,1,1)\n",
    "frame[frame.Birth >= pd.datetime(1985,1,1)]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "#выбираем строки, удовлетворяющие пересечению условий\n",
    "frame[(frame.Birth >= pd.datetime(1985,1,1)) &\n",
    "      (frame.City != 'Москва')]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "#выбираем строки, удовлетворяющие объединению условий\n",
    "frame[(frame.Birth >= pd.datetime(1985,1,1)) |\n",
    "      (frame.City == 'Волгоград')]"
   ]
  }
 ],
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