dfr arg-unique for dataframe

Returns indexes for unique values.

Signature

> dfr arg-unique

Input/output types:

input	output
any	any

Examples

Returns indexes for unique values

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

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