Series.combine(other, func, fill_value=None)[source]

Combine the Series with a Series or scalar according to func.

Combine the Series and other using func to perform elementwise selection for combined Series. fill_value is assumed when value is missing at some index from one of the two objects being combined.

otherSeries or scalar

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


Function that takes two scalars as inputs and returns an element.

fill_valuescalar, optional

The value to assume when an index is missing from one Series or the other. The default specifies to use the appropriate NaN value for the underlying dtype of the Series.


The result of combining the Series with the other object.

See also


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


Consider 2 Datasets s1 and s2 containing highest clocked speeds of different birds.

>>> s1 = pd.Series({'falcon': 330.0, 'eagle': 160.0})
>>> s1
falcon    330.0
eagle     160.0
dtype: float64
>>> s2 = pd.Series({'falcon': 345.0, 'eagle': 200.0, 'duck': 30.0})
>>> s2
falcon    345.0
eagle     200.0
duck       30.0
dtype: float64

Now, to combine the two datasets and view the highest speeds of the birds across the two datasets

>>> s1.combine(s2, max)
duck        NaN
eagle     200.0
falcon    345.0
dtype: float64

In the previous example, the resulting value for duck is missing, because the maximum of a NaN and a float is a NaN. So, in the example, we set fill_value=0, so the maximum value returned will be the value from some dataset.

>>> s1.combine(s2, max, fill_value=0)
duck       30.0
eagle     200.0
falcon    345.0
dtype: float64