이렇게 써도 되는지는 몰랐다 보기 깔끔한 듯! df['col_3'] = df[['col_1','col_2']].apply(lambda x: f(*x), axis=1) 이렇게 쓸줄만 알았었음 df['col_3'] = df.apply(lambda x: f(x['col 1'], x['col 2']), axis=1) * Reference https://stackoverflow.com/questions/13331698/how-to-apply-a-function-to-two-columns-of-pandas-dataframe How to apply a function to two columns of Pandas dataframe Suppose I have a df which has columns of 'ID', 'c..