polars.Series.pct_change

Series.pct_change(
    n: int | IntoExprColumn = 1,
) → Series

Computes percentage change between values.

Percentage change (as fraction) between current element and most-recent non-null element at least n period(s) before the current element.

Computes the change from the previous row by default.

Parameters:

n

periods to shift for forming percent change.

Notes

Null values are preserved. If you’re coming from pandas, this matches their fill_method=None behaviour.

Examples

>>> pl.Series(range(10)).pct_change()
shape: (10,)
Series: '' [f64]
[
    null
    inf
    1.0
    0.5
    0.333333
    0.25
    0.2
    0.166667
    0.142857
    0.125
]

>>> pl.Series([1, 2, 4, 8, 16, 32, 64, 128, 256, 512]).pct_change(2)
shape: (10,)
Series: '' [f64]
[
    null
    null
    3.0
    3.0
    3.0
    3.0
    3.0
    3.0
    3.0
    3.0
]