按两列分组并计算每种组合在熊猫中的出现

按两列分组并计算每种组合在熊猫中的出现

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