notebook/02-修炼筛选基本功（作业）.ipynb

{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "在 [修炼筛选基本功](02-修炼筛选基本功.ipynb) 中，我们学会了如何按照行、列、行列、布尔条件进行筛选数据，这里我们来做一些练习。\n",
    "\n",
    "- 每隔5行数据进行筛选一次\n",
    "- 将数据进行反转（第一行变为倒数第一行，第二行变为倒数第二行...）\n",
    "- 筛选出用户、评分时间这两列数据\n",
    "- 筛选出第1行的用户、评分时间这两列数据\n",
    "- 筛选id为19用户对id为50、52的电影的评分"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {
    "ExecuteTime": {
     "end_time": "2018-07-27T06:51:55.009988Z",
     "start_time": "2018-07-27T06:51:54.692132Z"
    }
   },
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div>\n",
       "<style>\n",
       "    .dataframe thead tr:only-child th {\n",
       "        text-align: right;\n",
       "    }\n",
       "\n",
       "    .dataframe thead th {\n",
       "        text-align: left;\n",
       "    }\n",
       "\n",
       "    .dataframe tbody tr th {\n",
       "        vertical-align: top;\n",
       "    }\n",
       "</style>\n",
       "<table border=\"1\" class=\"dataframe\">\n",
       "  <thead>\n",
       "    <tr style=\"text-align: right;\">\n",
       "      <th></th>\n",
       "      <th>userId</th>\n",
       "      <th>movieId</th>\n",
       "      <th>rating</th>\n",
       "      <th>timestamp</th>\n",
       "      <th>title</th>\n",
       "      <th>genres</th>\n",
       "      <th>imdbId</th>\n",
       "      <th>tmdbId</th>\n",
       "    </tr>\n",
       "  </thead>\n",
       "  <tbody>\n",
       "    <tr>\n",
       "      <th>0</th>\n",
       "      <td>1</td>\n",
       "      <td>31</td>\n",
       "      <td>2.5</td>\n",
       "      <td>1260759144</td>\n",
       "      <td>Dangerous Minds (1995)</td>\n",
       "      <td>Drama</td>\n",
       "      <td>112792.0</td>\n",
       "      <td>9909.0</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1</th>\n",
       "      <td>1</td>\n",
       "      <td>1029</td>\n",
       "      <td>3.0</td>\n",
       "      <td>1260759179</td>\n",
       "      <td>Dumbo (1941)</td>\n",
       "      <td>Animation|Children|Drama|Musical</td>\n",
       "      <td>33563.0</td>\n",
       "      <td>11360.0</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2</th>\n",
       "      <td>1</td>\n",
       "      <td>1061</td>\n",
       "      <td>3.0</td>\n",
       "      <td>1260759182</td>\n",
       "      <td>Sleepers (1996)</td>\n",
       "      <td>Thriller</td>\n",
       "      <td>117665.0</td>\n",
       "      <td>819.0</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>3</th>\n",
       "      <td>1</td>\n",
       "      <td>1129</td>\n",
       "      <td>2.0</td>\n",
       "      <td>1260759185</td>\n",
       "      <td>Escape from New York (1981)</td>\n",
       "      <td>Action|Adventure|Sci-Fi|Thriller</td>\n",
       "      <td>82340.0</td>\n",
       "      <td>1103.0</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>4</th>\n",
       "      <td>1</td>\n",
       "      <td>1172</td>\n",
       "      <td>4.0</td>\n",
       "      <td>1260759205</td>\n",
       "      <td>Cinema Paradiso (Nuovo cinema Paradiso) (1989)</td>\n",
       "      <td>Drama</td>\n",
       "      <td>95765.0</td>\n",
       "      <td>11216.0</td>\n",
       "    </tr>\n",
       "  </tbody>\n",
       "</table>\n",
       "</div>"
      ],
      "text/plain": [
       "   userId  movieId  rating   timestamp  \\\n",
       "0       1       31     2.5  1260759144   \n",
       "1       1     1029     3.0  1260759179   \n",
       "2       1     1061     3.0  1260759182   \n",
       "3       1     1129     2.0  1260759185   \n",
       "4       1     1172     4.0  1260759205   \n",
       "\n",
       "                                            title  \\\n",
       "0                          Dangerous Minds (1995)   \n",
       "1                                    Dumbo (1941)   \n",
       "2                                 Sleepers (1996)   \n",
       "3                     Escape from New York (1981)   \n",
       "4  Cinema Paradiso (Nuovo cinema Paradiso) (1989)   \n",
       "\n",
       "                             genres    imdbId   tmdbId  \n",
       "0                             Drama  112792.0   9909.0  \n",
       "1  Animation|Children|Drama|Musical   33563.0  11360.0  \n",
       "2                          Thriller  117665.0    819.0  \n",
       "3  Action|Adventure|Sci-Fi|Thriller   82340.0   1103.0  \n",
       "4                             Drama   95765.0  11216.0  "
      ]
     },
     "execution_count": 1,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "import pandas as pd\n",
    "import numpy as np\n",
    "\n",
    "data = pd.read_csv(\"../data/ml-latest-small/user_for_movie_ratings_summary.csv\", encoding=\"gbk\")\n",
    "data.head()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## 每隔5行数据进行筛选一次"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {
    "ExecuteTime": {
     "end_time": "2018-07-27T06:51:55.067142Z",
     "start_time": "2018-07-27T06:51:55.019011Z"
    }
   },
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div>\n",
       "<style>\n",
       "    .dataframe thead tr:only-child th {\n",
       "        text-align: right;\n",
       "    }\n",
       "\n",
       "    .dataframe thead th {\n",
       "        text-align: left;\n",
       "    }\n",
       "\n",
       "    .dataframe tbody tr th {\n",
       "        vertical-align: top;\n",
       "    }\n",
       "</style>\n",
       "<table border=\"1\" class=\"dataframe\">\n",
       "  <thead>\n",
       "    <tr style=\"text-align: right;\">\n",
       "      <th></th>\n",
       "      <th>userId</th>\n",
       "      <th>movieId</th>\n",
       "      <th>rating</th>\n",
       "      <th>timestamp</th>\n",
       "      <th>title</th>\n",
       "      <th>genres</th>\n",
       "      <th>imdbId</th>\n",
       "      <th>tmdbId</th>\n",
       "    </tr>\n",
       "  </thead>\n",
       "  <tbody>\n",
       "    <tr>\n",
       "      <th>0</th>\n",
       "      <td>1</td>\n",
       "      <td>31</td>\n",
       "      <td>2.5</td>\n",
       "      <td>1260759144</td>\n",
       "      <td>Dangerous Minds (1995)</td>\n",
       "      <td>Drama</td>\n",
       "      <td>112792.0</td>\n",
       "      <td>9909.0</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>6</th>\n",
       "      <td>1</td>\n",
       "      <td>1287</td>\n",
       "      <td>2.0</td>\n",
       "      <td>1260759187</td>\n",
       "      <td>Ben-Hur (1959)</td>\n",
       "      <td>Action|Adventure|Drama</td>\n",
       "      <td>52618.0</td>\n",
       "      <td>665.0</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>12</th>\n",
       "      <td>1</td>\n",
       "      <td>1953</td>\n",
       "      <td>4.0</td>\n",
       "      <td>1260759191</td>\n",
       "      <td>French Connection, The (1971)</td>\n",
       "      <td>Action|Crime|Thriller</td>\n",
       "      <td>67116.0</td>\n",
       "      <td>1051.0</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>18</th>\n",
       "      <td>1</td>\n",
       "      <td>2968</td>\n",
       "      <td>1.0</td>\n",
       "      <td>1260759200</td>\n",
       "      <td>Time Bandits (1981)</td>\n",
       "      <td>Adventure|Comedy|Fantasy|Sci-Fi</td>\n",
       "      <td>81633.0</td>\n",
       "      <td>36819.0</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>24</th>\n",
       "      <td>2</td>\n",
       "      <td>50</td>\n",
       "      <td>4.0</td>\n",
       "      <td>835355586</td>\n",
       "      <td>Usual Suspects, The (1995)</td>\n",
       "      <td>Crime|Mystery|Thriller</td>\n",
       "      <td>114814.0</td>\n",
       "      <td>629.0</td>\n",
       "    </tr>\n",
       "  </tbody>\n",
       "</table>\n",
       "</div>"
      ],
      "text/plain": [
       "    userId  movieId  rating   timestamp                          title  \\\n",
       "0        1       31     2.5  1260759144         Dangerous Minds (1995)   \n",
       "6        1     1287     2.0  1260759187                 Ben-Hur (1959)   \n",
       "12       1     1953     4.0  1260759191  French Connection, The (1971)   \n",
       "18       1     2968     1.0  1260759200            Time Bandits (1981)   \n",
       "24       2       50     4.0   835355586     Usual Suspects, The (1995)   \n",
       "\n",
       "                             genres    imdbId   tmdbId  \n",
       "0                             Drama  112792.0   9909.0  \n",
       "6            Action|Adventure|Drama   52618.0    665.0  \n",
       "12            Action|Crime|Thriller   67116.0   1051.0  \n",
       "18  Adventure|Comedy|Fantasy|Sci-Fi   81633.0  36819.0  \n",
       "24           Crime|Mystery|Thriller  114814.0    629.0  "
      ]
     },
     "execution_count": 2,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "data[::6].head()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## 将数据进行反转"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {
    "ExecuteTime": {
     "end_time": "2018-07-27T06:51:55.124295Z",
     "start_time": "2018-07-27T06:51:55.072155Z"
    }
   },
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div>\n",
       "<style>\n",
       "    .dataframe thead tr:only-child th {\n",
       "        text-align: right;\n",
       "    }\n",
       "\n",
       "    .dataframe thead th {\n",
       "        text-align: left;\n",
       "    }\n",
       "\n",
       "    .dataframe tbody tr th {\n",
       "        vertical-align: top;\n",
       "    }\n",
       "</style>\n",
       "<table border=\"1\" class=\"dataframe\">\n",
       "  <thead>\n",
       "    <tr style=\"text-align: right;\">\n",
       "      <th></th>\n",
       "      <th>userId</th>\n",
       "      <th>movieId</th>\n",
       "      <th>rating</th>\n",
       "      <th>timestamp</th>\n",
       "      <th>title</th>\n",
       "      <th>genres</th>\n",
       "      <th>imdbId</th>\n",
       "      <th>tmdbId</th>\n",
       "    </tr>\n",
       "  </thead>\n",
       "  <tbody>\n",
       "    <tr>\n",
       "      <th>100003</th>\n",
       "      <td>671</td>\n",
       "      <td>6565</td>\n",
       "      <td>3.5</td>\n",
       "      <td>1074784724</td>\n",
       "      <td>Seabiscuit (2003)</td>\n",
       "      <td>Drama</td>\n",
       "      <td>329575.0</td>\n",
       "      <td>4464.0</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>100002</th>\n",
       "      <td>671</td>\n",
       "      <td>6385</td>\n",
       "      <td>2.5</td>\n",
       "      <td>1070979663</td>\n",
       "      <td>Whale Rider (2002)</td>\n",
       "      <td>Drama</td>\n",
       "      <td>298228.0</td>\n",
       "      <td>1088.0</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>100001</th>\n",
       "      <td>671</td>\n",
       "      <td>6365</td>\n",
       "      <td>4.0</td>\n",
       "      <td>1070940363</td>\n",
       "      <td>Matrix Reloaded, The (2003)</td>\n",
       "      <td>Action|Adventure|Sci-Fi|Thriller|IMAX</td>\n",
       "      <td>234215.0</td>\n",
       "      <td>604.0</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>100000</th>\n",
       "      <td>671</td>\n",
       "      <td>6269</td>\n",
       "      <td>4.0</td>\n",
       "      <td>1065149201</td>\n",
       "      <td>Stevie (2002)</td>\n",
       "      <td>Documentary</td>\n",
       "      <td>334416.0</td>\n",
       "      <td>51927.0</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>99999</th>\n",
       "      <td>671</td>\n",
       "      <td>6268</td>\n",
       "      <td>2.5</td>\n",
       "      <td>1065579370</td>\n",
       "      <td>Raising Victor Vargas (2002)</td>\n",
       "      <td>Comedy|Drama|Romance</td>\n",
       "      <td>316188.0</td>\n",
       "      <td>25461.0</td>\n",
       "    </tr>\n",
       "  </tbody>\n",
       "</table>\n",
       "</div>"
      ],
      "text/plain": [
       "        userId  movieId  rating   timestamp                         title  \\\n",
       "100003     671     6565     3.5  1074784724             Seabiscuit (2003)   \n",
       "100002     671     6385     2.5  1070979663            Whale Rider (2002)   \n",
       "100001     671     6365     4.0  1070940363   Matrix Reloaded, The (2003)   \n",
       "100000     671     6269     4.0  1065149201                 Stevie (2002)   \n",
       "99999      671     6268     2.5  1065579370  Raising Victor Vargas (2002)   \n",
       "\n",
       "                                       genres    imdbId   tmdbId  \n",
       "100003                                  Drama  329575.0   4464.0  \n",
       "100002                                  Drama  298228.0   1088.0  \n",
       "100001  Action|Adventure|Sci-Fi|Thriller|IMAX  234215.0    604.0  \n",
       "100000                            Documentary  334416.0  51927.0  \n",
       "99999                    Comedy|Drama|Romance  316188.0  25461.0  "
      ]
     },
     "execution_count": 3,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "data[::-1].head()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## 筛选出用户、评分时间这两列数据"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {
    "ExecuteTime": {
     "end_time": "2018-07-27T06:51:55.153374Z",
     "start_time": "2018-07-27T06:51:55.129309Z"
    }
   },
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div>\n",
       "<style>\n",
       "    .dataframe thead tr:only-child th {\n",
       "        text-align: right;\n",
       "    }\n",
       "\n",
       "    .dataframe thead th {\n",
       "        text-align: left;\n",
       "    }\n",
       "\n",
       "    .dataframe tbody tr th {\n",
       "        vertical-align: top;\n",
       "    }\n",
       "</style>\n",
       "<table border=\"1\" class=\"dataframe\">\n",
       "  <thead>\n",
       "    <tr style=\"text-align: right;\">\n",
       "      <th></th>\n",
       "      <th>userId</th>\n",
       "      <th>timestamp</th>\n",
       "    </tr>\n",
       "  </thead>\n",
       "  <tbody>\n",
       "    <tr>\n",
       "      <th>0</th>\n",
       "      <td>1</td>\n",
       "      <td>1260759144</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>1</th>\n",
       "      <td>1</td>\n",
       "      <td>1260759179</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>2</th>\n",
       "      <td>1</td>\n",
       "      <td>1260759182</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>3</th>\n",
       "      <td>1</td>\n",
       "      <td>1260759185</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>4</th>\n",
       "      <td>1</td>\n",
       "      <td>1260759205</td>\n",
       "    </tr>\n",
       "  </tbody>\n",
       "</table>\n",
       "</div>"
      ],
      "text/plain": [
       "   userId   timestamp\n",
       "0       1  1260759144\n",
       "1       1  1260759179\n",
       "2       1  1260759182\n",
       "3       1  1260759185\n",
       "4       1  1260759205"
      ]
     },
     "execution_count": 4,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "data[[\"userId\", \"timestamp\"]].head()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## 筛选出第1行的用户、评分时间这两列数据"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {
    "ExecuteTime": {
     "end_time": "2018-07-27T06:51:55.188468Z",
     "start_time": "2018-07-27T06:51:55.157385Z"
    }
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "userId                1\n",
       "timestamp    1260759179\n",
       "Name: 1, dtype: object"
      ]
     },
     "execution_count": 5,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "data.loc[1, [\"userId\", \"timestamp\"]]"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## 筛选id为19用户对id为50、52的电影的评分"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {
    "ExecuteTime": {
     "end_time": "2018-07-27T06:51:55.241613Z",
     "start_time": "2018-07-27T06:51:55.192480Z"
    }
   },
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div>\n",
       "<style>\n",
       "    .dataframe thead tr:only-child th {\n",
       "        text-align: right;\n",
       "    }\n",
       "\n",
       "    .dataframe thead th {\n",
       "        text-align: left;\n",
       "    }\n",
       "\n",
       "    .dataframe tbody tr th {\n",
       "        vertical-align: top;\n",
       "    }\n",
       "</style>\n",
       "<table border=\"1\" class=\"dataframe\">\n",
       "  <thead>\n",
       "    <tr style=\"text-align: right;\">\n",
       "      <th></th>\n",
       "      <th>userId</th>\n",
       "      <th>movieId</th>\n",
       "      <th>rating</th>\n",
       "      <th>timestamp</th>\n",
       "      <th>title</th>\n",
       "      <th>genres</th>\n",
       "      <th>imdbId</th>\n",
       "      <th>tmdbId</th>\n",
       "    </tr>\n",
       "  </thead>\n",
       "  <tbody>\n",
       "    <tr>\n",
       "      <th>3130</th>\n",
       "      <td>19</td>\n",
       "      <td>50</td>\n",
       "      <td>4.0</td>\n",
       "      <td>855192835</td>\n",
       "      <td>Usual Suspects, The (1995)</td>\n",
       "      <td>Crime|Mystery|Thriller</td>\n",
       "      <td>114814.0</td>\n",
       "      <td>629.0</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>3131</th>\n",
       "      <td>19</td>\n",
       "      <td>52</td>\n",
       "      <td>3.0</td>\n",
       "      <td>855190167</td>\n",
       "      <td>Mighty Aphrodite (1995)</td>\n",
       "      <td>Comedy|Drama|Romance</td>\n",
       "      <td>113819.0</td>\n",
       "      <td>11448.0</td>\n",
       "    </tr>\n",
       "  </tbody>\n",
       "</table>\n",
       "</div>"
      ],
      "text/plain": [
       "      userId  movieId  rating  timestamp                       title  \\\n",
       "3130      19       50     4.0  855192835  Usual Suspects, The (1995)   \n",
       "3131      19       52     3.0  855190167     Mighty Aphrodite (1995)   \n",
       "\n",
       "                      genres    imdbId   tmdbId  \n",
       "3130  Crime|Mystery|Thriller  114814.0    629.0  \n",
       "3131    Comedy|Drama|Romance  113819.0  11448.0  "
      ]
     },
     "execution_count": 6,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "data[(data.userId == 19) & (data.movieId.isin([50, 52]))]"
   ]
  }
 ],
 "metadata": {
  "kernelspec": {
   "display_name": "Python 3",
   "language": "python",
   "name": "python3"
  },
  "language_info": {
   "codemirror_mode": {
    "name": "ipython",
    "version": 3
   },
   "file_extension": ".py",
   "mimetype": "text/x-python",
   "name": "python",
   "nbconvert_exporter": "python",
   "pygments_lexer": "ipython3",
   "version": "3.5.4"
  }
 },
 "nbformat": 4,
 "nbformat_minor": 2
}