pandas DataFrame合并求和列 [英] Pandas DataFrame merge summing column

问题描述

我正在尝试合并两个DataFrames求和列值.

I'm trying to merge two DataFrames summing columns value.

>>> print(df1)
   id name  weight
0   1    A       0
1   2    B      10
2   3    C      10

>>> print(df2)
   id name  weight
0   2    B      15
1   3    C      10

在合并公用列中的相似值时，我需要对weight个值求和.

I need to sum weight values during merging for similar values in the common column.

merge = pd.merge(df1, df2, how='inner')

所以输出将类似于以下内容.

So the output will be something like following.

   id name  weight
1   2    B      25
2   3    C      20

推荐答案

In [41]: pd.merge(df1, df2, on=['id', 'name']).set_index(['id', 'name']).sum(axis=1)
Out[41]: 
id  name
2   B       25
3   C       20
dtype: int64

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