python - Make new column in Panda dataframe by adding values from other columns

Question

I have a dataframe with values like

A B
1 4
2 6
3 9

I need to add a new column by adding values from column A and B, like

A B C
1 4 5
2 6 8
3 9 12

I believe this can be done using lambda function, but I can't figure out how to do it.

Answer 1

Very simple:

df['C'] = df['A'] + df['B']