polars std

Creates a std expression for an aggregation of std value from columns in a dataframe.

warning This command requires a plugin The polars std 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.

Command Type

plugin

Signature

> polars std {flags}

Input/output types:

input	output
polars_expression	polars_expression
polars_selector	polars_expression
polars_dataframe	polars_dataframe
polars_lazyframe	polars_lazyframe

Examples

Std value from columns in a dataframe

> [[a b]; [6 2] [4 2] [2 2]] | polars into-df | polars std | polars collect
╭───┬──────┬──────╮
│ # │  a   │  b   │
├───┼──────┼──────┤
│ 0 │ 2.00 │ 0.00 │
╰───┴──────┴──────╯

Std aggregation for a group-by

> [[a b]; [one 2] [one 2] [two 1] [two 1]]
            | polars into-df
            | polars group-by a
            | polars agg (polars col b | polars std)
            | polars collect
            | polars sort-by a
╭───┬─────┬──────╮
│ # │  a  │  b   │
├───┼─────┼──────┤
│ 0 │ one │ 0.00 │
│ 1 │ two │ 0.00 │
╰───┴─────┴──────╯

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