您可以在apply中添加result_type='expand':

扩展":类似列表的结果将变成列.

‘expand’ : list-like results will be turned into columns.

df[['add', 'multiply']]=df.apply(lambda x: add_multiply(x['col1'], x['col2']),axis=1,
                             result_type='expand')

或调用数据框构造函数:

Or call a dataframe constructor:

df[['add', 'multiply']]=pd.DataFrame(df.apply(lambda x: add_multiply(x['col1'], 
                                    x['col2']), axis=1).tolist())

   col1  col2  add  multiply
0     1     3    4         3
1     2     4    6         8