columns for filters

Given a record or table, produce a list of its columns' names.

Signature

> columns {flags}

Input/output types:

inputoutput
recordlist<string>
tablelist<string>

Examples

Get the columns from the record

> { acronym:PWD, meaning:'Print Working Directory' } | columns
╭───┬─────────╮
 0  acronym 
 1  meaning 
╰───┴─────────╯

Get the columns from the table

> [[name,age,grade]; [bill,20,a]] | columns
╭───┬───────╮
 0  name  
 1  age   
 2  grade 
╰───┴───────╯

Get the first column from the table

> [[name,age,grade]; [bill,20,a]] | columns | first

Get the second column from the table

> [[name,age,grade]; [bill,20,a]] | columns | select 1

Notes

This is a counterpart to values, which produces a list of columns' values.