1
在DataFrame“data_to_rank”中,我有一列“r_DTS”。 data_to_rank [ 'r_DTS']表示:熊猫groupby:缺少组密钥?
Name: r_DTS, dtype: category
Categories (4, object): [Bottom < 2 < Top < Missing]
当我做:
>>> b = data_to_rank.groupby(['r_DTS'])
>>> for key, group in b: print(key)
Bottom
2
Top
Missing
然而,当我组通过与其它变量 'r_DTS', “丢失” 在 “r_DTS” disapear。
>>> a = data_to_rank.groupby(['GRADE','r_DTS'])
>>> for key, group in a: print(key)
('HY', 'Bottom')
('HY', '2')
('HY', 'Top')
('IG', 'Bottom')
('IG', '2')
('IG', 'Top')
('HY','Missing')和('IG','Missing')在哪里?