python dataframe两列分组计数并取最大

import pandas as pd
import numpy as np
df = pd.DataFrame({'job': ['sale', 'sale', 'sale', 'market', 'market', 'market', 'market', 'market'],
'source': ['A', 'A', 'C', 'D', 'E', 'C', 'B', 'C']})
print(df)
print('1'*60)

# #groupby count方式一
df_groupby = df.groupby(['job', 'source'])['source'].count().reset_index(name='count')  #加不上set_index
print(df_groupby)
print('2'*60)

# groupby count方式二
df_groupby = df['source'].groupby(df['job']).value_counts() .reset_index(name='count')
print(df_groupby)
print('3'*60)

haha = df_groupby.sort_values(['job', 'count'], ascending=False).groupby('job').head(1)#head参数可改，分组选取前n
print(haha)

结果如下：

      job source
0    sale      A
1    sale      A
2    sale      C
3  market      D
4  market      E
5  market      C
6  market      B
7  market      C
111111111111111111111111111111111111111111111111111111111111
      job source  count
0  market      B      1
1  market      C      2
2  market      D      1
3  market      E      1
4    sale      A      2
5    sale      C      1
222222222222222222222222222222222222222222222222222222222222
      job source  count
0  market      C      2
1  market      B      1
2  market      D      1
3  market      E      1
4    sale      A      2
5    sale      C      1
333333333333333333333333333333333333333333333333333333333333
      job source  count
4    sale      A      2
0  market      C      2

Process finished with exit code 0