Sum one column to multiple columns in pandas

Question

I ran into a very odd error today. I am trying to add the values of one column to multiple columns but pandas is throwing a memory error. I looked around but I must be wording the problem poorly because I found a bunch of pd.concat questions.

Imagine the following data frame:

import pandas as pd
df = pd.DataFrame({c1:[100,200,300],c2:[10,20,30],c3:[1,2,3]})

I want to reassign columns c1 and c2 so that they become their original values plus c3 . I thought this would work:

df[['c1','c2']] = df[['c1','c2']] + df['c3']

---------------------------------------------------------------------------
MemoryError

I solved it doing the following, but there has to be a better solution.

df[['c1','c2']].apply(lambda x: x + df['c3'])

What am I missing? Is there a way to use an axis argument to make the first method work? Is there a way to use .sum() to achieve this?

Answer 1

@ALollz posted the solution as a comment, so here it is as an answer. Hope it helps someone in the future:

df[['c1','c2']] = df[['c1','c2']].add(df['c3'], axis=0)

I was not specifying the axis argument, hence the importance of .add() .