Expanding.
sum
Calculate expanding sum of given DataFrame or Series.
For compatibility with other expanding methods. Has no effect on the computed value.
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