F# array_chunk for Sequence

Question

I'm having some trouble making a sequence. Basically I need to chop a sequence into a sequence of arrays. Seq.windowed almost does it but I don't want duplicate elements.

I can get what I want by reading everything into an array first but I'd rather use a sequence.

let array_chunk s (a:int[]) =
    Array.init (a.Length / s) (fun i -> Array.sub a (i * s) s)

someSequence |> Seq.to_array |> array_chunk 5

Answer 1

Here's another approach with some pattern matching - it looks more like *.iter, and I've got it spitting out lists rather than arrays, since that's how I usually like my data.

let sequence_in_lists_of_length_n_with_acc (s: seq<'a>) n acc = seq {
use e = s.GetEnumerator()
let rec next_with_acc acc =
  match e.MoveNext(), acc with
  | true, a when List.length a + 1 = n ->  
    yield (List.rev (e.Current :: a))
    next_with_acc []
  | true, _ -> next_with_acc (e.Current :: acc)
  | false, _ ->
    f(List.rev acc)
  ()
next_with_acc []

}