polars selector first for expression
Creates a selector that selects the first column(s) by index.
Signature
> polars selector first {flags} (n)
Parameters
-
n: Number of columns to select from the beginning (default: 1).
Input/output types:
| input | output |
|---|---|
| any | polars_selector |
Examples
Create a selector for the first column
> polars selector first
Create a selector for the first 3 columns
> polars selector first 3
Create a new column from the first column using with-column
> [[a b c]; [1 2 3] [4 5 6]]
| polars into-df
| polars with-column ((polars selector first) * 10 | polars as a_times_10)
| polars collect
╭───┬───┬───┬───┬────────────╮
│ # │ a │ b │ c │ a_times_10 │
├───┼───┼───┼───┼────────────┤
│ 0 │ 1 │ 2 │ 3 │ 10 │
│ 1 │ 4 │ 5 │ 6 │ 40 │
╰───┴───┴───┴───┴────────────╯
Copyright © 2019–2026 The Nushell Project DevelopersLicensed under the MIT License.
https://www.nushell.sh/commands/docs/polars_selector_first.html
