polars shift for [dataframe or lazyframe](/commands/categories/dataframe or lazyframe.md)

Shifts the values by a given period.

This command requires a plugin

The polars shift command resides in the polars plugin. To use this command, you must install and register nu_plugin_polars. See the Plugins chapter in the book for more information.

Signature

> polars shift {flags} (period)

Flags

  • --fill, -f {any}: Expression used to fill the null values (lazy df)

Parameters

  • period: shift period

Input/output types:

inputoutput
polars_dataframepolars_dataframe
polars_lazyframepolars_lazyframe
polars_expressionpolars_expression

Examples

Shifts the values by a given period

> [1 2 2 3 3] | polars into-df | polars shift 2 | polars drop-nulls
╭───┬───╮
│ # │ 0 │
├───┼───┤
│ 0 │ 1 │
│ 1 │ 2 │
│ 2 │ 2 │
╰───┴───╯

Shifts the values by a given period, fill absent values with 0

> [1 2 2 3 3] | polars into-lazy | polars shift 2 --fill 0 | polars collect
╭───┬───╮
│ # │ 0 │
├───┼───┤
│ 0 │ 0 │
│ 1 │ 0 │
│ 2 │ 1 │
│ 3 │ 2 │
│ 4 │ 2 │
╰───┴───╯

Shift values of a column, fill absent values with 0

> [[a]; [1] [2] [2] [3] [3]]
                    | polars into-lazy
                    | polars with-column {b: (polars col a | polars shift 2 --fill 0)}
                    | polars collect
╭───┬───┬───╮
│ # │ a │ b │
├───┼───┼───┤
│ 0 │ 1 │ 0 │
│ 1 │ 2 │ 0 │
│ 2 │ 2 │ 1 │
│ 3 │ 3 │ 2 │
│ 4 │ 3 │ 2 │
╰───┴───┴───╯