Pandas , Sum Values of two columns from 2 DFs

Question

I have two data-frames as shown below (sample data) :

df1:

Key1    Val1    Val2    Val3
A       2       1       3
B       2       2       2
C       3       3       4
D       4       4       2
E       5       6       5

df2:

Key1    Seasionality
A       1.2
B       -1
C       1
D       1.2
E       1.5

How can we add Seasonality to df1 (val1, val2 , val3) where df1.key1 = df2.key1 .

Desired Output:

Key1    Val1    Val2    Vale
A       3.2     2.2     4.2
B       1       1       1
C       4       4       5
D       5.2     5.2     3.2
E       6.5     7.5     6.5

Previously i had similar requirement where i need to add columns from two different df with same keys but they had similar column names, so i was able to use :

pd.concat([df1,df2]).groupby(level=0).sum()

But can not think of a solution to above problem.

Answer 1

One possible solution is to align the keys temporarily:

df1.set_index('Key1', inplace=True)
df2.set_index('Key1', inplace=True)
df1 = df1.add(df2['Seasionality'], axis=0)
df1.reset_index(inplace=True)