python - First non-null value per row from a list of Pandas columns

Question

If I've got a DataFrame in pandas which looks something like:

    A   B   C
0   1 NaN   2
1 NaN   3 NaN
2 NaN   4   5
3 NaN NaN NaN

How can I get the first non-null value from each row? E.g. for the above, I'd like to get: [1, 3, 4, None] (or equivalent Series).

Answer 1

Fill the nans from the left with fillna, then get the leftmost column:

df.fillna(method='bfill', axis=1).iloc[:, 0]