python - Add/subtract dataframes with different column labels

Question

I'm trying to add/subtract two dataframes with different column labels. Is it possible to do this without renaming the columns to align them? I would like to keep the original labels.

Answer 1

Consider dataframes A and B

A = pd.DataFrame([[1, 2], [3, 4]], ['a', 'b'], ['A', 'B'])
B = pd.DataFrame([[1, 2], [3, 4]], ['c', 'd'], ['C', 'D'])

---

A

B

Add them together and we have a mess.

A + B

Add their underlying arrays

A.values + B.values

array([[2, 4],
       [6, 8]])

That's closer to what we want.

To get what you asked for, you need to decide which dataframe has the columns and index you want and add the values of the other to the dataframe you chose. Let's say I choose to keep A's indices.

A + B.values

That ought to do it!