Re: [Caml-list] Preferred Way to Split a List

[Christophe Raffalli <Christophe.Raffalli@univ-savoie.fr>]

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Or

let split l n =
  let rec aux acc l n =
     if n = 0 then List.rev acc, l
     else match l with
        [] -> List.rev acc, []
     | hd::l -> aux (hd::acc) l (n-1)
  in aux [] l n

This is tail recursive, it does not use magic nor  references
and keed the original ordering of the list.

Finally, I did in the past some testing  comparing a tail-rec append or map
using magic and the composition of rev and rev-append or rev-map ...
There was no noticable difference, because the extra cost  of
mutability (regarding the managment of the grey val list) compensate
the extra call to reverse.

So I think I would write split the way shown above if ordering matters.

Cheers,
Christophe
>
> Alain
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