将列拆分到dataframe中

import pandas as pd

data = {'col1': ['A,B,C', 'D,E,F', 'G,H,I'],
        'col2': ['1,2,3', '4,5,6', '7,8,9']}
df = pd.DataFrame(data)

df[['col1_1', 'col1_2', 'col1_3']] = df['col1'].str.split(',', expand=True)
df[['col2_1', 'col2_2', 'col2_3']] = df['col2'].str.split(',', expand=True)

   col1   col2 col1_1 col1_2 col1_3 col2_1 col2_2 col2_3
0  A,B,C  1,2,3      A      B      C      1      2      3
1  D,E,F  4,5,6      D      E      F      4      5      6
2  G,H,I  7,8,9      G      H      I      7      8      9