Pandas Series: expanding() function

Last update on September 15 2022 12:54:08 (UTC/GMT +8 hours)

Expanding transformations in Pandas

The expanding() function is used to provide expanding transformations.

Syntax:

Series.expanding(self, min_periods=1, center=False, axis=0)

Parameters:

Name	Description	Type/Default Value	Required / Optional
min_periods	Minimum number of observations in window required to have a value (otherwise result is NA).	int Default Value : 1	Required
center	Set the labels at the center of the window.	bool Default Value : False	Required
axis	If the axis is a MultiIndex (hierarchical), group by a particular level or levels.	nt or str Default Value : 0	Required

Returns: a Window sub-classed for the particular operation

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.

Python-Pandas Code:

import numpy as np
import pandas as pd
df = pd.DataFrame({'Q': [0, 2, 4, np.nan, 6]})
df

Output:

    Q
0	0.0
1	2.0
2	4.0
3	NaN
4	6.0

Python-Pandas Code:

import numpy as np
import pandas as pd
df = pd.DataFrame({'Q': [0, 2, 4, np.nan, 6]})
df.expanding(2).sum()

Output:

    Q
0	NaN
1	2.0
2	6.0
3	6.0
4	12.0

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