Item-Based Collaborative Filtering.ipynb

{
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  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Item-Based Collaborative Filtering\n",
    "\n",
    "https://www.youtube.com/watch?v=PA1XIDSHldc\n",
    "\n",
    "Building a movie recommender system using the MovieLens.org 100K user ratings and movie datasets\n",
    "\n",
    "The item-based filtering places an emphasis on the relationship between the movies as the basis of creating recommendations."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [],
   "source": [
    "# Import the necessary libraries\n",
    "import pandas as pd"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [],
   "source": [
    "# Load the ratings and movie datasets and merge into a single DataFrame\n",
    "# Ratings\n",
    "r_cols = ['user_id', 'movie_id', 'rating']\n",
    "ratings = pd.read_csv('./datasets/ml-100k/u.data', sep = '\\t', names = r_cols, usecols = range(3), encoding = 'latin-1')\n",
    "\n",
    "# Movies\n",
    "m_cols = ['movie_id', 'title']\n",
    "movies = pd.read_csv('./datasets/ml-100k/u.item', sep = '|', names = m_cols, usecols = range(2), encoding = 'latin-1')\n",
    "\n",
    "# Combine the movie and ratings DataFrames into a single DataFrame\n",
    "ratings = pd.merge(movies, ratings)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [
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      "text/plain": [
       "   movie_id             title  user_id  rating\n",
       "0         1  Toy Story (1995)      308       4\n",
       "1         1  Toy Story (1995)      287       5\n",
       "2         1  Toy Story (1995)      148       4\n",
       "3         1  Toy Story (1995)      280       4\n",
       "4         1  Toy Story (1995)       66       3"
      ]
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    "# Display the newly merged DataFrame\n",
    "ratings.head()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Use a pivot table to create a matrix of the users and movies they've rated"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {},
   "outputs": [
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       "<p>5 rows × 1664 columns</p>\n",
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      "text/plain": [
       "                           rating                                     \\\n",
       "title   'Til There Was You (1997) 1-900 (1994) 101 Dalmatians (1996)   \n",
       "user_id                                                                \n",
       "1                             NaN          NaN                   2.0   \n",
       "2                             NaN          NaN                   NaN   \n",
       "3                             NaN          NaN                   NaN   \n",
       "4                             NaN          NaN                   NaN   \n",
       "5                             NaN          NaN                   2.0   \n",
       "\n",
       "                                                                    \\\n",
       "title   12 Angry Men (1957) 187 (1997) 2 Days in the Valley (1996)   \n",
       "user_id                                                              \n",
       "1                       5.0        NaN                         NaN   \n",
       "2                       NaN        NaN                         NaN   \n",
       "3                       NaN        2.0                         NaN   \n",
       "4                       NaN        NaN                         NaN   \n",
       "5                       NaN        NaN                         NaN   \n",
       "\n",
       "                                                                          \\\n",
       "title   20,000 Leagues Under the Sea (1954) 2001: A Space Odyssey (1968)   \n",
       "user_id                                                                    \n",
       "1                                       3.0                          4.0   \n",
       "2                                       NaN                          NaN   \n",
       "3                                       NaN                          NaN   \n",
       "4                                       NaN                          NaN   \n",
       "5                                       NaN                          4.0   \n",
       "\n",
       "                                                                          \\\n",
       "title   3 Ninjas: High Noon At Mega Mountain (1998) 39 Steps, The (1935)   \n",
       "user_id                                                                    \n",
       "1                                               NaN                  NaN   \n",
       "2                                               1.0                  NaN   \n",
       "3                                               NaN                  NaN   \n",
       "4                                               NaN                  NaN   \n",
       "5                                               NaN                  NaN   \n",
       "\n",
       "                       ...                                     \\\n",
       "title                  ...                 Yankee Zulu (1994)   \n",
       "user_id                ...                                      \n",
       "1                      ...                                NaN   \n",
       "2                      ...                                NaN   \n",
       "3                      ...                                NaN   \n",
       "4                      ...                                NaN   \n",
       "5                      ...                                NaN   \n",
       "\n",
       "                                                      \\\n",
       "title   Year of the Horse (1997) You So Crazy (1994)   \n",
       "user_id                                                \n",
       "1                            NaN                 NaN   \n",
       "2                            NaN                 NaN   \n",
       "3                            NaN                 NaN   \n",
       "4                            NaN                 NaN   \n",
       "5                            NaN                 NaN   \n",
       "\n",
       "                                                                          \\\n",
       "title   Young Frankenstein (1974) Young Guns (1988) Young Guns II (1990)   \n",
       "user_id                                                                    \n",
       "1                             5.0               3.0                  NaN   \n",
       "2                             NaN               NaN                  NaN   \n",
       "3                             NaN               NaN                  NaN   \n",
       "4                             NaN               NaN                  NaN   \n",
       "5                             4.0               NaN                  NaN   \n",
       "\n",
       "                                                                               \\\n",
       "title   Young Poisoner's Handbook, The (1995) Zeus and Roxanne (1997) unknown   \n",
       "user_id                                                                         \n",
       "1                                         NaN                     NaN     4.0   \n",
       "2                                         NaN                     NaN     NaN   \n",
       "3                                         NaN                     NaN     NaN   \n",
       "4                                         NaN                     NaN     NaN   \n",
       "5                                         NaN                     NaN     4.0   \n",
       "\n",
       "                                            \n",
       "title   Á köldum klaka (Cold Fever) (1994)  \n",
       "user_id                                     \n",
       "1                                      NaN  \n",
       "2                                      NaN  \n",
       "3                                      NaN  \n",
       "4                                      NaN  \n",
       "5                                      NaN  \n",
       "\n",
       "[5 rows x 1664 columns]"
      ]
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     "execution_count": 4,
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   "source": [
    "# Create a pivot table that lists the user_id, uses the movie titles as columns, and displays the user ratings \n",
    "# for each movie\n",
    "userRatings = ratings.pivot_table(index = ['user_id'], columns = ['title'], values = ['rating'])   # Index = Rows\n",
    "userRatings.head()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Calculate the correlation score for each column pair in the matrix. \n",
    "\n",
    "This will create a table that lists the movie titles in both the index and columns, and displays the correlation between any given movie pair based on the rating scores provided (user rating vectors)."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {},
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       "    <tr>\n",
       "      <th>12 Angry Men (1957)</th>\n",
       "      <td>-0.5</td>\n",
       "      <td>NaN</td>\n",
       "      <td>-0.049890</td>\n",
       "      <td>1.000000</td>\n",
       "      <td>0.666667</td>\n",
       "      <td>0.256625</td>\n",
       "      <td>0.274772</td>\n",
       "      <td>0.178848</td>\n",
       "      <td>NaN</td>\n",
       "      <td>0.457176</td>\n",
       "      <td>...</td>\n",
       "      <td>NaN</td>\n",
       "      <td>NaN</td>\n",
       "      <td>NaN</td>\n",
       "      <td>0.096546</td>\n",
       "      <td>0.068944</td>\n",
       "      <td>-0.361961</td>\n",
       "      <td>0.144338</td>\n",
       "      <td>1.000000</td>\n",
       "      <td>1.0</td>\n",
       "      <td>NaN</td>\n",
       "    </tr>\n",
       "    <tr>\n",
       "      <th>187 (1997)</th>\n",
       "      <td>-0.5</td>\n",
       "      <td>NaN</td>\n",
       "      <td>0.269191</td>\n",
       "      <td>0.666667</td>\n",
       "      <td>1.000000</td>\n",
       "      <td>0.596644</td>\n",
       "      <td>NaN</td>\n",
       "      <td>-0.554700</td>\n",
       "      <td>NaN</td>\n",
       "      <td>1.000000</td>\n",
       "      <td>...</td>\n",
       "      <td>NaN</td>\n",
       "      <td>0.866025</td>\n",
       "      <td>NaN</td>\n",
       "      <td>0.455233</td>\n",
       "      <td>-0.500000</td>\n",
       "      <td>0.500000</td>\n",
       "      <td>0.475327</td>\n",
       "      <td>NaN</td>\n",
       "      <td>NaN</td>\n",
       "      <td>NaN</td>\n",
       "    </tr>\n",
       "  </tbody>\n",
       "</table>\n",
       "<p>5 rows × 1664 columns</p>\n",
       "</div>"
      ],
      "text/plain": [
       "                                                    rating               \\\n",
       "title                            'Til There Was You (1997) 1-900 (1994)   \n",
       "       title                                                              \n",
       "rating 'Til There Was You (1997)                       1.0          NaN   \n",
       "       1-900 (1994)                                    NaN          1.0   \n",
       "       101 Dalmatians (1996)                          -1.0          NaN   \n",
       "       12 Angry Men (1957)                            -0.5          NaN   \n",
       "       187 (1997)                                     -0.5          NaN   \n",
       "\n",
       "                                                                            \\\n",
       "title                            101 Dalmatians (1996) 12 Angry Men (1957)   \n",
       "       title                                                                 \n",
       "rating 'Til There Was You (1997)             -1.000000           -0.500000   \n",
       "       1-900 (1994)                                NaN                 NaN   \n",
       "       101 Dalmatians (1996)                  1.000000           -0.049890   \n",
       "       12 Angry Men (1957)                   -0.049890            1.000000   \n",
       "       187 (1997)                             0.269191            0.666667   \n",
       "\n",
       "                                                                         \\\n",
       "title                            187 (1997) 2 Days in the Valley (1996)   \n",
       "       title                                                              \n",
       "rating 'Til There Was You (1997)  -0.500000                    0.522233   \n",
       "       1-900 (1994)                     NaN                         NaN   \n",
       "       101 Dalmatians (1996)       0.269191                    0.048973   \n",
       "       12 Angry Men (1957)         0.666667                    0.256625   \n",
       "       187 (1997)                  1.000000                    0.596644   \n",
       "\n",
       "                                                                      \\\n",
       "title                            20,000 Leagues Under the Sea (1954)   \n",
       "       title                                                           \n",
       "rating 'Til There Was You (1997)                                 NaN   \n",
       "       1-900 (1994)                                              NaN   \n",
       "       101 Dalmatians (1996)                                0.266928   \n",
       "       12 Angry Men (1957)                                  0.274772   \n",
       "       187 (1997)                                                NaN   \n",
       "\n",
       "                                                               \\\n",
       "title                            2001: A Space Odyssey (1968)   \n",
       "       title                                                    \n",
       "rating 'Til There Was You (1997)                    -0.426401   \n",
       "       1-900 (1994)                                 -0.981981   \n",
       "       101 Dalmatians (1996)                        -0.043407   \n",
       "       12 Angry Men (1957)                           0.178848   \n",
       "       187 (1997)                                   -0.554700   \n",
       "\n",
       "                                                                              \\\n",
       "title                            3 Ninjas: High Noon At Mega Mountain (1998)   \n",
       "       title                                                                   \n",
       "rating 'Til There Was You (1997)                                         NaN   \n",
       "       1-900 (1994)                                                      NaN   \n",
       "       101 Dalmatians (1996)                                             NaN   \n",
       "       12 Angry Men (1957)                                               NaN   \n",
       "       187 (1997)                                                        NaN   \n",
       "\n",
       "                                                       \\\n",
       "title                            39 Steps, The (1935)   \n",
       "       title                                            \n",
       "rating 'Til There Was You (1997)                  NaN   \n",
       "       1-900 (1994)                               NaN   \n",
       "       101 Dalmatians (1996)                 0.111111   \n",
       "       12 Angry Men (1957)                   0.457176   \n",
       "       187 (1997)                            1.000000   \n",
       "\n",
       "                                                ...                  \\\n",
       "title                                           ...                   \n",
       "       title                                    ...                   \n",
       "rating 'Til There Was You (1997)                ...                   \n",
       "       1-900 (1994)                             ...                   \n",
       "       101 Dalmatians (1996)                    ...                   \n",
       "       12 Angry Men (1957)                      ...                   \n",
       "       187 (1997)                               ...                   \n",
       "\n",
       "                                                                              \\\n",
       "title                            Yankee Zulu (1994) Year of the Horse (1997)   \n",
       "       title                                                                   \n",
       "rating 'Til There Was You (1997)                NaN                      NaN   \n",
       "       1-900 (1994)                             NaN                      NaN   \n",
       "       101 Dalmatians (1996)                    NaN                -1.000000   \n",
       "       12 Angry Men (1957)                      NaN                      NaN   \n",
       "       187 (1997)                               NaN                 0.866025   \n",
       "\n",
       "                                                      \\\n",
       "title                            You So Crazy (1994)   \n",
       "       title                                           \n",
       "rating 'Til There Was You (1997)                 NaN   \n",
       "       1-900 (1994)                              NaN   \n",
       "       101 Dalmatians (1996)                     NaN   \n",
       "       12 Angry Men (1957)                       NaN   \n",
       "       187 (1997)                                NaN   \n",
       "\n",
       "                                                                              \\\n",
       "title                            Young Frankenstein (1974) Young Guns (1988)   \n",
       "       title                                                                   \n",
       "rating 'Til There Was You (1997)                       NaN               NaN   \n",
       "       1-900 (1994)                              -0.944911               NaN   \n",
       "       101 Dalmatians (1996)                      0.158840          0.119234   \n",
       "       12 Angry Men (1957)                        0.096546          0.068944   \n",
       "       187 (1997)                                 0.455233         -0.500000   \n",
       "\n",
       "                                                       \\\n",
       "title                            Young Guns II (1990)   \n",
       "       title                                            \n",
       "rating 'Til There Was You (1997)                  NaN   \n",
       "       1-900 (1994)                               NaN   \n",
       "       101 Dalmatians (1996)                 0.680414   \n",
       "       12 Angry Men (1957)                  -0.361961   \n",
       "       187 (1997)                            0.500000   \n",
       "\n",
       "                                                                        \\\n",
       "title                            Young Poisoner's Handbook, The (1995)   \n",
       "       title                                                             \n",
       "rating 'Til There Was You (1997)                                   NaN   \n",
       "       1-900 (1994)                                                NaN   \n",
       "       101 Dalmatians (1996)                                  0.000000   \n",
       "       12 Angry Men (1957)                                    0.144338   \n",
       "       187 (1997)                                             0.475327   \n",
       "\n",
       "                                                                  \\\n",
       "title                            Zeus and Roxanne (1997) unknown   \n",
       "       title                                                       \n",
       "rating 'Til There Was You (1997)                     NaN     NaN   \n",
       "       1-900 (1994)                                  NaN     NaN   \n",
       "       101 Dalmatians (1996)                    0.707107     NaN   \n",
       "       12 Angry Men (1957)                      1.000000     1.0   \n",
       "       187 (1997)                                    NaN     NaN   \n",
       "\n",
       "                                                                     \n",
       "title                            Á köldum klaka (Cold Fever) (1994)  \n",
       "       title                                                         \n",
       "rating 'Til There Was You (1997)                                NaN  \n",
       "       1-900 (1994)                                             NaN  \n",
       "       101 Dalmatians (1996)                                    NaN  \n",
       "       12 Angry Men (1957)                                      NaN  \n",
       "       187 (1997)                                               NaN  \n",
       "\n",
       "[5 rows x 1664 columns]"
      ]
     },
     "execution_count": 5,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "# Create a correlation matrix that compares the correlation scores of the movies\n",
    "corrMatrix = userRatings.corr()\n",
    "corrMatrix.head()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "The filter needs to be adjusted to display the results of movies that several people rated together. This will also help determine which titles are the most popular/easily recognizable. To do this, the min_periods argument will be used to pull results for movie rating pairs where at least 100 users rated them."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {},
   "outputs": [
    {
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       "      <td>NaN</td>\n",
       "      <td>NaN</td>\n",
       "      <td>NaN</td>\n",
       "      <td>NaN</td>\n",
       "      <td>NaN</td>\n",
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       "      <td>NaN</td>\n",
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       "      <td>NaN</td>\n",
       "      <td>NaN</td>\n",
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       "<p>5 rows × 1664 columns</p>\n",
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      ],
      "text/plain": [
       "                                                    rating               \\\n",
       "title                            'Til There Was You (1997) 1-900 (1994)   \n",
       "       title                                                              \n",
       "rating 'Til There Was You (1997)                       NaN          NaN   \n",
       "       1-900 (1994)                                    NaN          NaN   \n",
       "       101 Dalmatians (1996)                           NaN          NaN   \n",
       "       12 Angry Men (1957)                             NaN          NaN   \n",
       "       187 (1997)                                      NaN          NaN   \n",
       "\n",
       "                                                                            \\\n",
       "title                            101 Dalmatians (1996) 12 Angry Men (1957)   \n",
       "       title                                                                 \n",
       "rating 'Til There Was You (1997)                   NaN                 NaN   \n",
       "       1-900 (1994)                                NaN                 NaN   \n",
       "       101 Dalmatians (1996)                       1.0                 NaN   \n",
       "       12 Angry Men (1957)                         NaN                 1.0   \n",
       "       187 (1997)                                  NaN                 NaN   \n",
       "\n",
       "                                                                         \\\n",
       "title                            187 (1997) 2 Days in the Valley (1996)   \n",
       "       title                                                              \n",
       "rating 'Til There Was You (1997)        NaN                         NaN   \n",
       "       1-900 (1994)                     NaN                         NaN   \n",
       "       101 Dalmatians (1996)            NaN                         NaN   \n",
       "       12 Angry Men (1957)              NaN                         NaN   \n",
       "       187 (1997)                       NaN                         NaN   \n",
       "\n",
       "                                                                      \\\n",
       "title                            20,000 Leagues Under the Sea (1954)   \n",
       "       title                                                           \n",
       "rating 'Til There Was You (1997)                                 NaN   \n",
       "       1-900 (1994)                                              NaN   \n",
       "       101 Dalmatians (1996)                                     NaN   \n",
       "       12 Angry Men (1957)                                       NaN   \n",
       "       187 (1997)                                                NaN   \n",
       "\n",
       "                                                               \\\n",
       "title                            2001: A Space Odyssey (1968)   \n",
       "       title                                                    \n",
       "rating 'Til There Was You (1997)                          NaN   \n",
       "       1-900 (1994)                                       NaN   \n",
       "       101 Dalmatians (1996)                              NaN   \n",
       "       12 Angry Men (1957)                                NaN   \n",
       "       187 (1997)                                         NaN   \n",
       "\n",
       "                                                                              \\\n",
       "title                            3 Ninjas: High Noon At Mega Mountain (1998)   \n",
       "       title                                                                   \n",
       "rating 'Til There Was You (1997)                                         NaN   \n",
       "       1-900 (1994)                                                      NaN   \n",
       "       101 Dalmatians (1996)                                             NaN   \n",
       "       12 Angry Men (1957)                                               NaN   \n",
       "       187 (1997)                                                        NaN   \n",
       "\n",
       "                                                       \\\n",
       "title                            39 Steps, The (1935)   \n",
       "       title                                            \n",
       "rating 'Til There Was You (1997)                  NaN   \n",
       "       1-900 (1994)                               NaN   \n",
       "       101 Dalmatians (1996)                      NaN   \n",
       "       12 Angry Men (1957)                        NaN   \n",
       "       187 (1997)                                 NaN   \n",
       "\n",
       "                                                ...                  \\\n",
       "title                                           ...                   \n",
       "       title                                    ...                   \n",
       "rating 'Til There Was You (1997)                ...                   \n",
       "       1-900 (1994)                             ...                   \n",
       "       101 Dalmatians (1996)                    ...                   \n",
       "       12 Angry Men (1957)                      ...                   \n",
       "       187 (1997)                               ...                   \n",
       "\n",
       "                                                                              \\\n",
       "title                            Yankee Zulu (1994) Year of the Horse (1997)   \n",
       "       title                                                                   \n",
       "rating 'Til There Was You (1997)                NaN                      NaN   \n",
       "       1-900 (1994)                             NaN                      NaN   \n",
       "       101 Dalmatians (1996)                    NaN                      NaN   \n",
       "       12 Angry Men (1957)                      NaN                      NaN   \n",
       "       187 (1997)                               NaN                      NaN   \n",
       "\n",
       "                                                      \\\n",
       "title                            You So Crazy (1994)   \n",
       "       title                                           \n",
       "rating 'Til There Was You (1997)                 NaN   \n",
       "       1-900 (1994)                              NaN   \n",
       "       101 Dalmatians (1996)                     NaN   \n",
       "       12 Angry Men (1957)                       NaN   \n",
       "       187 (1997)                                NaN   \n",
       "\n",
       "                                                                              \\\n",
       "title                            Young Frankenstein (1974) Young Guns (1988)   \n",
       "       title                                                                   \n",
       "rating 'Til There Was You (1997)                       NaN               NaN   \n",
       "       1-900 (1994)                                    NaN               NaN   \n",
       "       101 Dalmatians (1996)                           NaN               NaN   \n",
       "       12 Angry Men (1957)                             NaN               NaN   \n",
       "       187 (1997)                                      NaN               NaN   \n",
       "\n",
       "                                                       \\\n",
       "title                            Young Guns II (1990)   \n",
       "       title                                            \n",
       "rating 'Til There Was You (1997)                  NaN   \n",
       "       1-900 (1994)                               NaN   \n",
       "       101 Dalmatians (1996)                      NaN   \n",
       "       12 Angry Men (1957)                        NaN   \n",
       "       187 (1997)                                 NaN   \n",
       "\n",
       "                                                                        \\\n",
       "title                            Young Poisoner's Handbook, The (1995)   \n",
       "       title                                                             \n",
       "rating 'Til There Was You (1997)                                   NaN   \n",
       "       1-900 (1994)                                                NaN   \n",
       "       101 Dalmatians (1996)                                       NaN   \n",
       "       12 Angry Men (1957)                                         NaN   \n",
       "       187 (1997)                                                  NaN   \n",
       "\n",
       "                                                                  \\\n",
       "title                            Zeus and Roxanne (1997) unknown   \n",
       "       title                                                       \n",
       "rating 'Til There Was You (1997)                     NaN     NaN   \n",
       "       1-900 (1994)                                  NaN     NaN   \n",
       "       101 Dalmatians (1996)                         NaN     NaN   \n",
       "       12 Angry Men (1957)                           NaN     NaN   \n",
       "       187 (1997)                                    NaN     NaN   \n",
       "\n",
       "                                                                     \n",
       "title                            Á köldum klaka (Cold Fever) (1994)  \n",
       "       title                                                         \n",
       "rating 'Til There Was You (1997)                                NaN  \n",
       "       1-900 (1994)                                             NaN  \n",
       "       101 Dalmatians (1996)                                    NaN  \n",
       "       12 Angry Men (1957)                                      NaN  \n",
       "       187 (1997)                                               NaN  \n",
       "\n",
       "[5 rows x 1664 columns]"
      ]
     },
     "execution_count": 6,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "# Use the Pearson correlation score with movies that had at least 100 ratings to determine the correlation scores\n",
    "corrMatrix = userRatings.corr(method = 'pearson', min_periods = 100)\n",
    "corrMatrix.head()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### More work needed here\n",
    "\n",
    "Add new user at user number 0 <br>\n",
    "Rate 3-5 movies for new user"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Create a new user 0 as a test case"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "        title                                             \n",
       "rating  Austin Powers: International Man of Mystery (1997)    4.0\n",
       "        Beavis and Butt-head Do America (1996)                2.0\n",
       "        Cable Guy, The (1996)                                 2.0\n",
       "        Chasing Amy (1997)                                    4.5\n",
       "        Close Shave, A (1995)                                 3.0\n",
       "        Con Air (1997)                                        1.0\n",
       "        Dead Man Walking (1995)                               3.0\n",
       "        Devil's Advocate, The (1997)                          2.0\n",
       "        Devil's Own, The (1997)                               2.0\n",
       "        Face/Off (1997)                                       5.0\n",
       "        Fargo (1996)                                          3.0\n",
       "        Fathers' Day (1997)                                   3.0\n",
       "        Fierce Creatures (1997)                               3.0\n",
       "        Fifth Element, The (1997)                             4.0\n",
       "        George of the Jungle (1997)                           2.0\n",
       "        Grosse Pointe Blank (1997)                            4.0\n",
       "        Jackie Chan's First Strike (1996)                     2.0\n",
       "        Leaving Las Vegas (1995)                              4.0\n",
       "        Liar Liar (1997)                                      3.0\n",
       "        Mars Attacks! (1996)                                  3.0\n",
       "        Men in Black (1997)                                   4.0\n",
       "        Michael (1996)                                        3.0\n",
       "        Mission: Impossible (1996)                            4.0\n",
       "        People vs. Larry Flynt, The (1996)                    4.0\n",
       "        Primal Fear (1996)                                    3.0\n",
       "        Private Parts (1997)                                  4.0\n",
       "        Ransom (1996)                                         3.0\n",
       "        Return of the Jedi (1983)                             4.0\n",
       "        Rock, The (1996)                                      3.0\n",
       "        Scream (1996)                                         4.0\n",
       "        Sleepers (1996)                                       4.0\n",
       "        Star Trek: First Contact (1996)                       3.0\n",
       "        Star Wars (1977)                                      4.0\n",
       "        Starship Troopers (1997)                              3.0\n",
       "        Titanic (1997)                                        4.0\n",
       "        Trainspotting (1996)                                  5.0\n",
       "        Truth About Cats & Dogs, The (1996)                   3.0\n",
       "        Twelve Monkeys (1995)                                 4.0\n",
       "        Twister (1996)                                        3.0\n",
       "        Willy Wonka and the Chocolate Factory (1971)          3.0\n",
       "Name: 32, dtype: float64"
      ]
     },
     "execution_count": 7,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "# Pull a single user record to work with - Displays all of the titles user #32 rated\n",
    "myRatings = userRatings.loc[32].dropna()\n",
    "myRatings"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Go through each of the rated titles to build a list of potential recommendations based on the user's rated titles.\n",
    "\n",
    "For each of the rated movies, a list of similar movies will be pulled from the correlation matrix. Those correlations will then be scaled based on the user ratings, so that the movies that were liked most will have a greater impact."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## More work here\n",
    "\n",
    "Adjust the for loop to appear similarly to the tutorial (7:17)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 13,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Adding similar movies for ('rating', 'Austin Powers: International Man of Mystery (1997)')...\n",
      "Adding similar movies for ('rating', 'Beavis and Butt-head Do America (1996)')...\n",
      "Adding similar movies for ('rating', 'Cable Guy, The (1996)')...\n",
      "Adding similar movies for ('rating', 'Chasing Amy (1997)')...\n",
      "Adding similar movies for ('rating', 'Close Shave, A (1995)')...\n",
      "Adding similar movies for ('rating', 'Con Air (1997)')...\n",
      "Adding similar movies for ('rating', 'Dead Man Walking (1995)')...\n",
      "Adding similar movies for ('rating', \"Devil's Advocate, The (1997)\")...\n",
      "Adding similar movies for ('rating', \"Devil's Own, The (1997)\")...\n",
      "Adding similar movies for ('rating', 'Face/Off (1997)')...\n",
      "Adding similar movies for ('rating', 'Fargo (1996)')...\n",
      "Adding similar movies for ('rating', \"Fathers' Day (1997)\")...\n",
      "Adding similar movies for ('rating', 'Fierce Creatures (1997)')...\n",
      "Adding similar movies for ('rating', 'Fifth Element, The (1997)')...\n",
      "Adding similar movies for ('rating', 'George of the Jungle (1997)')...\n",
      "Adding similar movies for ('rating', 'Grosse Pointe Blank (1997)')...\n",
      "Adding similar movies for ('rating', \"Jackie Chan's First Strike (1996)\")...\n",
      "Adding similar movies for ('rating', 'Leaving Las Vegas (1995)')...\n",
      "Adding similar movies for ('rating', 'Liar Liar (1997)')...\n",
      "Adding similar movies for ('rating', 'Mars Attacks! (1996)')...\n",
      "Adding similar movies for ('rating', 'Men in Black (1997)')...\n",
      "Adding similar movies for ('rating', 'Michael (1996)')...\n",
      "Adding similar movies for ('rating', 'Mission: Impossible (1996)')...\n",
      "Adding similar movies for ('rating', 'People vs. Larry Flynt, The (1996)')...\n",
      "Adding similar movies for ('rating', 'Primal Fear (1996)')...\n",
      "Adding similar movies for ('rating', 'Private Parts (1997)')...\n",
      "Adding similar movies for ('rating', 'Ransom (1996)')...\n",
      "Adding similar movies for ('rating', 'Return of the Jedi (1983)')...\n",
      "Adding similar movies for ('rating', 'Rock, The (1996)')...\n",
      "Adding similar movies for ('rating', 'Scream (1996)')...\n",
      "Adding similar movies for ('rating', 'Sleepers (1996)')...\n",
      "Adding similar movies for ('rating', 'Star Trek: First Contact (1996)')...\n",
      "Adding similar movies for ('rating', 'Star Wars (1977)')...\n",
      "Adding similar movies for ('rating', 'Starship Troopers (1997)')...\n",
      "Adding similar movies for ('rating', 'Titanic (1997)')...\n",
      "Adding similar movies for ('rating', 'Trainspotting (1996)')...\n",
      "Adding similar movies for ('rating', 'Truth About Cats & Dogs, The (1996)')...\n",
      "Adding similar movies for ('rating', 'Twelve Monkeys (1995)')...\n",
      "Adding similar movies for ('rating', 'Twister (1996)')...\n",
      "Adding similar movies for ('rating', 'Willy Wonka and the Chocolate Factory (1971)')...\n",
      "Sort in decreasing order of similarity score: \n",
      "(rating, Face/Off (1997))                                       5.0\n",
      "(rating, Trainspotting (1996))                                  5.0\n",
      "(rating, Chasing Amy (1997))                                    4.5\n",
      "(rating, Austin Powers: International Man of Mystery (1997))    4.0\n",
      "(rating, Sleepers (1996))                                       4.0\n",
      "(rating, Fifth Element, The (1997))                             4.0\n",
      "(rating, Scream (1996))                                         4.0\n",
      "(rating, Grosse Pointe Blank (1997))                            4.0\n",
      "(rating, Leaving Las Vegas (1995))                              4.0\n",
      "(rating, Star Wars (1977))                                      4.0\n",
      "dtype: float64\n"
     ]
    }
   ],
   "source": [
    "simCandidates = pd.Series()\n",
    "for i in range(0, len(myRatings.index)):\n",
    "    print(\"Adding similar movies for \" + str(myRatings.index[i]) + \"...\")\n",
    "    # Retrieve similar movies to the ones already rated\n",
    "    sims = corrMatrix[myRatings.index[i]].dropna()\n",
    "    # Scale the similarity based on how the user rated the movie\n",
    "    sims = sims.map(lambda x: x * myRatings[i])\n",
    "    # Add the score to the list of similarity candidates\n",
    "    simCandidates = simCandidates.append(sims)\n",
    "\n",
    "# Check the results so far\n",
    "print(\"Sort in decreasing order of similarity score: \")\n",
    "simCandidates.sort_values(inplace = True, ascending = False)\n",
    "print(simCandidates.head(10))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# simCandidates = pd.Series()\n",
    "# for i in range(0, len(myRatings.index)):\n",
    "#     sims = corrMatrix[myRatings.index[i]].dropna()\n",
    "#     sims = sims.map(lambda x: x * myRatings[i])\n",
    "#     simCandidates = simCandidates.append(sims)\n",
    "    \n",
    "# simCandidates.sort_values(inplace = True, ascending = False)\n",
    "# print (simCandidates.head(10))"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Use groupby to add together the scores from movies that show up more than once so that they will count more"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 14,
   "metadata": {},
   "outputs": [],
   "source": [
    "simCandidatessimCand = simCandidates.groupby(simCandidates.index).sum()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 15,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "(rating, Face/Off (1997))                       5.0\n",
       "(rating, Trainspotting (1996))                  5.0\n",
       "(rating, Chasing Amy (1997))                    4.5\n",
       "(rating, Star Wars (1977))                      4.0\n",
       "(rating, Titanic (1997))                        4.0\n",
       "(rating, Mission: Impossible (1996))            4.0\n",
       "(rating, Twelve Monkeys (1995))                 4.0\n",
       "(rating, Men in Black (1997))                   4.0\n",
       "(rating, People vs. Larry Flynt, The (1996))    4.0\n",
       "(rating, Return of the Jedi (1983))             4.0\n",
       "dtype: float64"
      ]
     },
     "execution_count": 15,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "simCandidates.sort_values(inplace = True, ascending = False)\n",
    "simCandidates.head(10)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Lastly, filter the movies that have already been rated, because recommending a movie that was already seen isn't helpful"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 16,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "(rating, Empire Strikes Back, The (1980))    2.991926\n",
       "(rating, Empire Strikes Back, The (1980))    2.884917\n",
       "(rating, Pulp Fiction (1994))                2.259531\n",
       "(rating, Raiders of the Lost Ark (1981))     2.144468\n",
       "(rating, GoldenEye (1995))                   2.033738\n",
       "(rating, Raising Arizona (1987))             1.955990\n",
       "(rating, Pretty Woman (1990))                1.918852\n",
       "(rating, Nutty Professor, The (1996))        1.895031\n",
       "(rating, Raiders of the Lost Ark (1981))     1.869562\n",
       "(rating, Back to the Future (1985))          1.813533\n",
       "dtype: float64"
      ]
     },
     "execution_count": 16,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "filteredSims = simCandidates.drop(myRatings.index)\n",
    "filteredSims.head(10)"
   ]
  }
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