select
for filters
Select only these columns or rows from the input. Opposite of `reject`.
Signature
> select {flags} ...rest
Flags
--ignore-errors, -i
: ignore missing data (make all cell path members optional)
Parameters
...rest
: The columns to select from the table.
Input/output types:
input | output |
---|---|
list<any> | any |
record | record |
table | table |
Examples
Select a column in a table
> [{a: a b: b}] | select a
╭───┬───╮
│ # │ a │
├───┼───┤
│ 0 │ a │
╰───┴───╯
Select a field in a record
> {a: a b: b} | select a
╭───┬───╮
│ a │ a │
╰───┴───╯
Select just the name
column
> ls | select name
Select the first four rows (this is the same as first 4
)
> ls | select 0 1 2 3
Select multiple columns
> [[name type size]; [Cargo.toml toml 1kb] [Cargo.lock toml 2kb]] | select name type
╭───┬────────────┬──────╮
│ # │ name │ type │
├───┼────────────┼──────┤
│ 0 │ Cargo.toml │ toml │
│ 1 │ Cargo.lock │ toml │
╰───┴────────────┴──────╯
Select multiple columns by spreading a list
> let cols = [name type]; [[name type size]; [Cargo.toml toml 1kb] [Cargo.lock toml 2kb]] | select ...$cols
╭───┬────────────┬──────╮
│ # │ name │ type │
├───┼────────────┼──────┤
│ 0 │ Cargo.toml │ toml │
│ 1 │ Cargo.lock │ toml │
╰───┴────────────┴──────╯
Notes
This differs from get
in that, rather than accessing the given value in the data structure, it removes all non-selected values from the structure. Hence, using select
on a table will produce a table, a list will produce a list, and a record will produce a record.