pandas.core.window.Expanding.sum — pandas 0.24.0rc1 documentation (original) (raw)

Expanding. sum(*args, **kwargs)[source]¶

Calculate expanding sum of given DataFrame or Series.

Parameters:	args, *kwargs For compatibility with other expanding methods. Has no effect on the computed value.
Returns:	Series or DataFrame Same type as the input, with the same index, containing the expanding sum.

See also

Series.sum

Reducing sum for Series.

DataFrame.sum

Reducing sum for DataFrame.

Examples

s = pd.Series([1, 2, 3, 4, 5]) s 0 1 1 2 2 3 3 4 4 5 dtype: int64

s.rolling(3).sum() 0 NaN 1 NaN 2 6.0 3 9.0 4 12.0 dtype: float64

s.expanding(3).sum() 0 NaN 1 NaN 2 6.0 3 10.0 4 15.0 dtype: float64

s.rolling(3, center=True).sum() 0 NaN 1 6.0 2 9.0 3 12.0 4 NaN dtype: float64

For DataFrame, each expanding sum is computed column-wise.

df = pd.DataFrame({"A": s, "B": s ** 2}) df A B 0 1 1 1 2 4 2 3 9 3 4 16 4 5 25

df.rolling(3).sum() A B 0 NaN NaN 1 NaN NaN 2 6.0 14.0 3 9.0 29.0 4 12.0 50.0