dfr std for expression

Creates a std expression for an aggregation of std value from columns in a dataframe.

WARNING

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

Signature

> dfr std {flags}

Input/output types:

inputoutput
anyany

Examples

Std value from columns in a dataframe

> [[a b]; [6 2] [4 2] [2 2]] | dfr into-df | dfr std
╭───┬──────┬──────╮
 # │  a   │  b   │
├───┼──────┼──────┤
 0  2.00  0.00 
╰───┴──────┴──────╯

Std 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 std)
╭───┬─────┬──────╮
 # │  a  │  b   │
├───┼─────┼──────┤
 0  one  0.00 
 1  two  0.00 
╰───┴─────┴──────╯