transpose of a list of lists

Question

I\'m trying to make a recursive function to get the transpose of a list of lists, n x p to p x n. But i\'m unable to do so. I\'ve been able to make

Answer 1

let rec transpose list = match list with
| []             -> []
| []   :: xss    -> transpose xss
| (x::xs) :: xss ->
    (x :: List.map List.hd xss) :: transpose (xs :: List.map List.tl xss)