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Membangun Recommendation Engine di Python

Robert O'Callaghan

Director of Data

Mengidentifikasi pasangan

0     User_223           The Great Gatsby <---| Dibaca oleh pengguna yang sama
1     User_223     The Catcher in the Rye <---|
2     User_131        The Lord of the Rings
3     User_965               Little Women <---| Dibaca oleh pengguna yang sama
4     User_965       Fifty Shades of Grey <---|
... ...
Membangun Recommendation Engine di Python

Permutasi vs kombinasi

Pengguna book_title
User_233 The Great Gatsby
User_233 The Catcher in the Rye

Menjadi:

Book A Book B
0 The Great Gatsby The Catcher in the Rye
1 The Catcher in the Rye The Great Gatsby

Buku yang muncul bersama The Great Gatsby -> The Catcher in the Rye

Buku yang muncul bersama The Catcher in the Rye -> The Great Gatsby

Membangun Recommendation Engine di Python

Membuat fungsi penggandengan

from itertools import permutations

def create_pairs(x):


  return pairs
Membangun Recommendation Engine di Python

Membuat fungsi penggandengan

from itertools import permutations

def create_pairs(x):
  pairs =                   permutations(x.values, 2)

  return pairs
  • permutations(list, length_of_permutations)) Membuat objek iterable berisi semua permutasi
Membangun Recommendation Engine di Python

Membuat fungsi penggandengan

from itertools import permutations

def create_pairs(x):
  pairs =              list(permutations(x.values, 2))

  return pairs
  • permutations(list, length_of_permutations)) Membuat objek iterable berisi semua permutasi

  • list() Mengonversi objek ini menjadi list yang dapat dipakai

Membangun Recommendation Engine di Python

Membuat fungsi penggandengan

from itertools import permutations

def create_pairs(x):
  pairs = pd.DataFrame(list(permutations(x.values, 2)), 
                           columns=['book_a','book_b'])
  return pairs
  • permutations(list, length_of_permutations)) Membuat objek iterable berisi semua permutasi

  • list() Mengonversi objek ini menjadi list yang dapat dipakai

  • pd.DataFrame() Mengonversi list menjadi DataFrame dengan kolom book_a dan book_b

Membangun Recommendation Engine di Python

Menerapkan fungsi ke data

book_pairs = book_df.groupby('userId')['book_title'].apply(perm_function)
print(book_pairs.head())
                                book_a                                   book_b
userId                                                   
User_223     0        The Great Gatsby                   The Catcher in the Rye
             1  The Catcher in the Rye                         The Great Gatsby
User_965     0            Little Women                        40 Shades of Grey
             1       40 Shades of Grey                             Little Women
User_773     0       The Twilight Saga    Harry Potter and the Sorcerer's Stone
                                                                            ...
Membangun Recommendation Engine di Python

Merapikan hasil

book_pairs = book_pairs.reset_index(drop=True)
print(book_pairs.head())
                     book_a                                   book_b
0          The Great Gatsby                   The Catcher in the Rye
1    The Catcher in the Rye                         The Great Gatsby
3              Little Women                        40 Shades of Grey
4         40 Shades of Grey                             Little Women
5         The Twilight Saga    Harry Potter and the Sorcerer's Stone
                                                                 ...
Membangun Recommendation Engine di Python

Menghitung pasangan

pair_counts = book_pairs.groupby(['book_a', 'book_b']).size()
book_a                                book_b                             
The Twilight Saga                     Fifty Shades of Grey           16
                                      Pride and Prejudice            12
                                                                    ...
pair_counts_df = pair_counts.to_frame(name = 'size').reset_index()
print(pair_counts_df.head())
     book_a                                book_b                       size    
1    The Twilight Saga                     Fifty Shades of Grey           16
2    The Twilight Saga                     Pride and Prejudice            12
                                                                         ...
Membangun Recommendation Engine di Python

Mencari rekomendasi

pair_counts_sorted = pair_counts_df.sort_values('size', ascending=False)
pair_counts_sorted[pair_counts_sorted['book_a'] == 'Lord of the Rings']
                  book_a                                     book_b size
137    Lord of the Rings                                 The Hobbit   12
147    Lord of the Rings      Harry Potter and the Sorcerer's Stone   10
143    Lord of the Rings                        The Colour of Magic    9
                                                                     ...
Membangun Recommendation Engine di Python

Ayo berlatih!

Membangun Recommendation Engine di Python

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