Task

Select certain elements from an Array into a new Array in a generic way.



To demonstrate, select all even numbers from an Array.

As an option, give a second solution which filters destructively,
by modifying the original Array rather than creating a new Array.




: filter  over swap execute select ;
10 iota "2 % not" filter . "\n" .
 
# [    0     2     4     6     8  ]