Pandas- Merging Two Dataframe By Sum The Values Of Columns And Index

I want to merge two datasets by indexes and columns. I want to merge entire dataset df1 = pd.DataFrame([[1, 0, 0], [0, 2, 0], [0, 0, 3]],columns=[1, 2, 3]) df1 1 2 3 0 1

Solution 1:

You can use :df1.add(df2, fill_value=0). It will add df2 into df1 also it will replace NAN value with 0.

>>> import numpy as np
>>> import pandas as pd
>>> df2 = pd.DataFrame([(10,9),(8,4),(7,np.nan)], columns=['a','b'])
>>> df1 = pd.DataFrame([(1,2),(3,4),(5,6)], columns=['a','b'])
>>> df1.add(df2, fill_value=0)

    a     b
0  11  11.0
1  11   8.0
2  12   6.0