也许这就是您想要的？
>>> data = pd.Dataframe({'user_id' : ['a1', 'a1', 'a1', 'a2','a2','a2','a3','a3','a3'], 'product_id' : ['p1','p1','p2','p1','p1','p1','p2','p2','p3']})>>> count_series = data.groupby(['user_id', 'product_id']).size()>>> count_seriesuser_id product_ida1 p1 2 p2 1a2 p1 3a3 p2 2 p3 1dtype: int64>>> new_df = count_series.to_frame(name = 'size').reset_index()>>> new_df user_id product_id size0 a1 p1 21 a1 p2 12 a2 p1 33 a3 p2 24 a3 p3 1>>> new_df['size']0 21 12 33 24 1Name: size, dtype: int64
