# pandas.Series.combine_first¶

Series.combine_first(self, other)[source]

Combine Series values, choosing the calling Series’s values first.

Parameters
otherSeries

The value(s) to be combined with the Series.

Returns
Series

The result of combining the Series with the other object.

Series.combine

Perform elementwise operation on two Series using a given function.

Notes

Result index will be the union of the two indexes.

Examples

>>> s1 = pd.Series([1, np.nan])
>>> s2 = pd.Series([3, 4])
>>> s1.combine_first(s2)
0    1.0
1    4.0
dtype: float64