polars std
for expression
Creates a std expression for an aggregation of std value from columns in a dataframe.
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.
Signature
> polars std {flags}
Input/output types:
input | output |
---|---|
any | any |
Examples
Std value from columns in a dataframe
> [[a b]; [6 2] [4 2] [2 2]] | polars into-df | polars std
╭───┬──────┬──────╮
│ # │ 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)
╭───┬─────┬──────╮
│ # │ a │ b │
├───┼─────┼──────┤
│ 0 │ one │ 0.00 │
│ 1 │ two │ 0.00 │
╰───┴─────┴──────╯