F# permutations

Question

I need to generate permutations on a given list. I managed to do it like this

let rec Permute (final, arr) = 
    if List.length arr > 0 then
        for          


        

Answer 1

In the spirit of Cyrl's suggestion, here's a sequence comprehension version

let rec permsOf xs =
  match xs with
  | [] -> List.toSeq([[]])
  | _ -> seq{ for x in xs do
               for xs' in permsOf (remove x xs) do
                 yield (x::xs')}

where remove is a simple function that removes a given element from a list

let rec remove x xs =
  match xs with [] -> [] | (x'::xs')-> if x=x' then xs' else x'::(remove x xs')