dfr n-unique for dataframe

Counts unique values.

WARNING

Dataframe commands were not shipped in the official binaries by default, you have to build it with --features=dataframe flag

Signature

> dfr n-unique {flags}

Input/output types:

inputoutput
anyany

Examples

Counts unique values

> [1 1 2 2 3 3 4] | dfr into-df | dfr n-unique
╭───┬──────────────╮
 # │ count_unique │
├───┼──────────────┤
 0             4 
╰───┴──────────────╯

Creates a is n-unique expression from a column

> dfr col a | dfr n-unique