Fill Blank Cells From Previous Columns Pandas Python

If I have a simple dataframe such as: q_1 q_1_mark q_2 q_2_mark TRUE a 1 c FALSE b 2 TRUE c 3 How could I fill in the bl

Solution 1:

df.q_2_mark.fillna(df.q_1_mark, inplace=True)

df
     q_1 q_1_mark  q_2 q_2_mark
0   True        a    1        c
1  False        b    2        b
2   True        c    3        c

Solution 2:

Assuming your dataframe is df, Try:

df.q_2_mark = df.q_2_mark.combine_first(df.q_1_mark) 

     q_1 q_1_mark  q_2 q_2_mark
0   True        a    1        c
1  False        b    2        b
2   True        c    3        c