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📜  计算由另一个 python 代码示例分组的一个变量的出现次数

📅  最后修改于: 2022-03-11 14:47:25.193000             🧑  作者: Mango

代码示例1
>>> 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_series
user_id  product_id
a1       p1            2
         p2            1
a2       p1            3
a3       p2            2
         p3            1
dtype: int64
>>> new_df = count_series.to_frame(name = 'size').reset_index()
>>> new_df
  user_id product_id  size
0      a1         p1     2
1      a1         p2     1
2      a2         p1     3
3      a3         p2     2
4      a3         p3     1
>>> new_df['size']
0    2
1    1
2    3
3    2
4    1
Name: size, dtype: int64