Python:dataframe str替换为部分小写字符串

Question

我的熊猫数据框如下。我只想删除包含-P到_P（之后是小写）和“-”的数据帧，然后用小写替换字符串

>>> data= ['AAP','AAPL','BRK-A','AAIC-PB','AAP-C','YAB-PP']
>>> a = pd.DataFrame(data,columns=['code'])
>>> a
      code
0      AAP
1     AAPL
2    BRK-A
3  AAIC-PB
4    AAP-C
5   YAB-PP
>>> a['code']=a['code'].str.replace('-P','_p')
>>> a
>>> a
      code
0      AAP
1     AAPL
2    BRK-A
3  AAIC_pB
4    AAP-C
5   YAB_pP
>>> a['code']=a['code'].str.replace('-','')
>>> a
      code
0      AAP
1     AAPL
2     BRKA
3  AAIC_pB
4     AAPC
5   YAB_pP
>>> 

所需输出为

      code
0      AAP
1     AAPL
2    BRKa
3  AAIC_pb
4    AAPc
5   YAB_pp

Answer 1

你可以做：

import pandas as pd

data= ['AAP','AAPL','BRK-A','AAIC-PB','AAP-C','YAB-PP']
a = pd.DataFrame(data,columns=['code'])


a['code'] = a['code'].str.replace('-(P.*)', lambda x: f'_{x.group(1).lower()}')
a['code'] = a['code'].str.replace('-(\w.*)', lambda x: x.group(1).lower())
print(a)

输出

      code
0      AAP
1     AAPL
2     BRKa
3  AAIC_pb
4     AAPc
5   YAB_pp

更新

在Python 3.6之前的版本中：

a['code'] = a['code'].str.replace('-(P.*)', lambda x: '_{}'.format(x.group(1).lower()))
a['code'] = a['code'].str.replace('-(\w.*)', lambda x: x.group(1).lower())
print(a)