polars.Series.diff

Series.diff(n: int = 1, null_behavior: NullBehavior = 'ignore') → Series

Calculate the first discrete difference between shifted items.

Parameters:

n

Number of slots to shift.

null_behavior{‘ignore’, ‘drop’}

How to handle null values.

Examples

>>> s = pl.Series("s", values=[20, 10, 30, 25, 35], dtype=pl.Int8)
>>> s.diff()
shape: (5,)
Series: 's' [i8]
[
    null
    -10
    20
    -5
    10
]

>>> s.diff(n=2)
shape: (5,)
Series: 's' [i8]
[
    null
    null
    10
    15
    5
]

>>> s.diff(n=2, null_behavior="drop")
shape: (3,)
Series: 's' [i8]
[
    10
    15
    5
]