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Sum columns of two information frames of different length

I have two data frames:

df1

    country  value
0      aa      1
1      bb      1
2      cc      5

df2

     country  value
0      cc      8
1      aa      2
2      MM      1
3      FF      6

How to get this dataframe ( df1

+ df2

) like this:

    country  value
0      aa      3
1      bb      1
2      MM      1
3      cc      13
4      FF      6
+3


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2 answers


Use set_index

and add

with fill_value=0

:

df1.set_index('country').add(df2.set_index('country'),fill_value=0).reset_index()


Output:

  country  value
0      FF    6.0
1      MM    1.0
2      aa    3.0
3      bb    1.0
4      cc   13.0
+4


source


You can first do the concatenation with pd.concat

and then use df.groupby

:



In [390]: pd.concat([df, df2]).groupby('country', as_index=False).sum()
Out[390]: 
  country  value
0      FF      6
1      MM      1
2      aa      3
3      bb      1
4      cc     13
+4


source






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