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 even? '(0 1 2 3 4 5 6 7 8 9))
'(0 2 4 6 8)
 