dfr var for expression

Create a var expression for an aggregation.

WARNING

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

Signature

> dfr var {flags}

Input/output types:

inputoutput
anyany

Examples

Var value from columns in a dataframe or aggregates columns to their var value

> [[a b]; [6 2] [4 2] [2 2]] | dfr into-df | dfr var
╭───┬──────┬──────╮
 # │  a   │  b   │
├───┼──────┼──────┤
 0  4.00  0.00 
╰───┴──────┴──────╯

Var aggregation for a group-by

> [[a b]; [one 2] [one 2] [two 1] [two 1]]
    | dfr into-df
    | dfr group-by a
    | dfr agg (dfr col b | dfr var)
╭───┬─────┬──────╮
 # │  a  │  b   │
├───┼─────┼──────┤
 0  one  0.00 
 1  two  0.00 
╰───┴─────┴──────╯