pandas.DataFrame.combine_first — pandas 0.24.0rc1 documentation (original) (raw)

DataFrame. combine_first(other)[source]¶

Update null elements with value in the same location in other.

Combine two DataFrame objects by filling null values in one DataFrame with non-null values from other DataFrame. The row and column indexes of the resulting DataFrame will be the union of the two.

See also

DataFrame.combine

Perform series-wise operation on two DataFrames using a given function.

Examples

df1 = pd.DataFrame({'A': [None, 0], 'B': [None, 4]}) df2 = pd.DataFrame({'A': [1, 1], 'B': [3, 3]}) df1.combine_first(df2) A B 0 1.0 3.0 1 0.0 4.0

Null values still persist if the location of that null value does not exist in other

df1 = pd.DataFrame({'A': [None, 0], 'B': [4, None]}) df2 = pd.DataFrame({'B': [3, 3], 'C': [1, 1]}, index=[1, 2]) df1.combine_first(df2) A B C 0 NaN 4.0 NaN 1 0.0 3.0 1.0 2 NaN 3.0 1.0