pandas.core.window.Expanding.sum

Expanding.sum(self, *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
Scroll To Top