On Wed, Apr 11, 2018, at 14:48, zljubi...@gmail.com wrote: > I have a dataframe: > [...]
This seems to work: df1 = pd.DataFrame( { 'A' : ['a', 'b', '', None, np.nan], 'B' : [None, np.nan, 'a', 'b', '']}) df1['C'] = df1[['A', 'B']].apply(lambda x: x[0] if x[1] in [None, '', np.nan] else x[1], axis = 1) Two notes: - Do apply() on axis = 1, so you process every row. - You lambda function wasn't entirely correct, if I understood what you wanted to do. Cheers, -- José María (Chema) Mateos https://rinzewind.org/blog-es || https://rinzewind.org/blog-en -- https://mail.python.org/mailman/listinfo/python-list