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Pandas Multiply 2D by 1D Dataframe

Time:11-17

Looking for an elegant way to multiply a 2D dataframe by a 1D series where the indices and column names align

df1 =

Index A B
1 1 5
2 2 6
3 3 7
4 4 8

df2 =

Coef
A 10
B 100

Something like...

df3 = df1.mul(df2)

To get :

Index A B
1 10 500
2 20 600
3 30 700
4 40 800

CodePudding user response:

There is no such thing as 1D DataFrame, you need to slice as Series to have 1D, then multiply (by default on axis=1):

df3 = df1.mul(df2['Coef'])

Output:

    A    B
1  10  500
2  20  600
3  30  700
4  40  800

If Index is a column:

df3 = df1.mul(df2['Coef']).combine_first(df1)[df1.columns]

Output:

   Index     A      B
0    1.0  10.0  500.0
1    2.0  20.0  600.0
2    3.0  30.0  700.0
3    4.0  40.0  800.0
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