pandas.Series.expanding — pandas 0.25.3 documentation (original) (raw)
Series. expanding(self, min_periods=1, center=False, axis=0)[source]¶
Provide expanding transformations.
New in version 0.18.0.
| Parameters: | min_periods : int, default 1 Minimum number of observations in window required to have a value (otherwise result is NA). center : bool, default False Set the labels at the center of the window. axis : int or str, default 0 |
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| Returns: | a Window sub-classed for the particular operation |
See also
Provides rolling window calculations.
Provides exponential weighted functions.
Notes
By default, the result is set to the right edge of the window. This can be changed to the center of the window by setting center=True.
Examples
df = pd.DataFrame({'B': [0, 1, 2, np.nan, 4]}) B 0 0.0 1 1.0 2 2.0 3 NaN 4 4.0
df.expanding(2).sum() B 0 NaN 1 1.0 2 3.0 3 3.0 4 7.0