Left join

使用 pandas 進行資料表連接

Aaren Stubberfield

Instructor

快速複習

Inner join 維恩圖

Left join

Left join 維恩圖

Left join

兩個資料表以 left join 合併的示意圖

新資料集

The Movie DB 標誌

多張電影海報拼貼

Movies 資料表

movies = pd.read_csv('tmdb_movies.csv')
print(movies.head())
print(movies.shape)

  id     original_title   popularity       release_date
0 257    Oliver Twist     20.415572        2005-09-23  
1 14290  Better Luck ...  3.877036         2002-01-12  
2 38365  Grown Ups        38.864027        2010-06-24  
3 9672   Infamous         3.6808959999...  2006-11-16  
4 12819  Alpha and Omega  12.300789        2010-09-17  
(4803, 4)

Tagline 資料表

taglines = pd.read_csv('tmdb_taglines.csv')
print(taglines.head())
print(taglines.shape)

  id      tagline
0 19995   Enter the World of Pandora.
1 285     At the end of the world, the adventure begins.
2 206647  A Plan No One Escapes
3 49026   The Legend Ends
4 49529   Lost in our world, found in another.
(3955, 2)

以 left join 合併

movies_taglines = movies.merge(taglines, on='id', how='left')
print(movies_taglines.head())

  id     original_title   popularity       release_date  tagline        
0 257    Oliver Twist     20.415572        2005-09-23    NaN            
1 14290  Better Luck ...  3.877036         2002-01-12    Never undere...
2 38365  Grown Ups        38.864027        2010-06-24    Boys will be...
3 9672   Infamous         3.6808959999...  2006-11-16    There's more...
4 12819  Alpha and Omega  12.300789        2010-09-17    A Pawsome 3D...

回傳的列數

print(movies_taglines.shape)

(4805, 5)

一起來練習吧！

使用 pandas 進行資料表連接