pyspark.pandas.window.Expanding.mean

Expanding.mean() → FrameLike[source]

Calculate the expanding mean of the values.

Note

the current implementation of this API uses Spark’s Window without specifying partition specification. This leads to move all data into single partition in single machine and could cause serious performance degradation. Avoid this method against very large dataset.

Returns
Series or DataFrame

Returned object type is determined by the caller of the expanding calculation.

See also

Series.expanding

Calling object with Series data.

DataFrame.expanding

Calling object with DataFrames.

Series.mean

Equivalent method for Series.

DataFrame.mean

Equivalent method for DataFrame.

Examples

The below examples will show expanding mean calculations with window sizes of two and three, respectively.

>>> s = ps.Series([1, 2, 3, 4])
>>> s.expanding(2).mean()
0    NaN
1    1.5
2    2.0
3    2.5
dtype: float64
>>> s.expanding(3).mean()
0    NaN
1    NaN
2    2.0
3    2.5
dtype: float64