Strain

Implement the `keep` and `discard` operation on collections.

Visit the strain exercise on Exercism to read the full instructions and download the exercise files.

Community Solutions

Lihat Solusi Komunitas

The following are the top 3 community solutions by stars:

💡 Lihat Solusi

fun keep f l =
  case l of
       [] => []
     | x::xs => if f x then x :: keep f xs else keep f xs

fun discard f l = keep (fn x => not (f x)) l