Dyadic filter

Rеturns elements from y for which x expression is true.

Syntax: <x> filter <y>; filter[<x>; <y>]

o)(0=x mod 2)filter x:1 5 6 8 11 17 20 21
6 8 20
o)filter[0=x mod 2;x:1 5 6 8 11 17 20 21]
6 8 20
o)(x>10)filter x:1 5 6 8 11 17 20 21
11 17 20 21
o)