3. 同时stack多组变量

  1. #  读取movie数据集，选取所有演员名和其Facebook likes
  2.  In[18]: movie = pd.read_csv('data/movie.csv')
  3.          actor = movie[['movie_title', 'actor_1_name', 'actor_2_name', 'actor_3_name', 
  4.                'actor_1_facebook_likes', 'actor_2_facebook_likes', 'actor_3_facebook_likes']]
  5.          actor.head()
  6. out[18]:

3. 同时stack多组变量 - 图1

  1. #  创建一个自定义函数，用来改变列名。wide_to_long要求分组的变量要有相同的数字结尾：
  2.  In[19]: def change_col_name(col_name):
  3.              col_name = col_name.replace('_name', '')
  4.              if 'facebook' in col_name:
  5.                  fb_idx = col_name.find('facebook')
  6.                  col_name = col_name[:5] + col_name[fb_idx - 1:] + col_name[5:fb_idx-1]
  7.              return col_name
  8.  In[20]: actor2 = actor.rename(columns=change_col_name)
  9.          actor2.head()
  10. out[20]:

3. 同时stack多组变量 - 图2

  1. #  使用wide_to_long函数，同时stack两列actor和Facebook
  2.  In[21]: stubs = ['actor', 'actor_facebook_likes']
  3.          actor2_tidy = pd.wide_to_long(actor2, 
  4.                                        stubnames=stubs, 
  5.                                        i=['movie_title'], 
  6.                                        j='actor_num', 
  7.                                        sep='_').reset_index()
  8.          actor2_tidy.head()
  9. out[21]:

3. 同时stack多组变量 - 图3

更多

  1. #  加载数据
  2.  In[22]: df = pd.read_csv('data/stackme.csv')
  3.          df
  4. out[22]:

3. 同时stack多组变量 - 图4

  1. #  对列重命名
  2.  In[23]: df2 = df.rename(columns = {'a1':'group1_a1', 'b2':'group1_b2',
  3.                                     'd':'group2_a1', 'e':'group2_b2'})
  4.          df2
  5. out[23]:

3. 同时stack多组变量 - 图5

  1. #  设定stubnames=['group1', 'group2']，对任何数字都起作用
  2.  In[24]: pd.wide_to_long(df2, 
  3.                          stubnames=['group1', 'group2'], 
  4.                          i=['State', 'Country', 'Test'], 
  5.                          j='Label', 
  6.                          suffix='.+', 
  7.                          sep='_')
  8. out[24]:

3. 同时stack多组变量 - 图6