如何在ocaml中删除int * int列表的标题

Question

Im trying to remove the head of list of type (int*int) using List.filter but i get an error. This is what i am trying to do:

List.filter (fun (i,j) -> List.tl <> List.hd) lst

Answer 1

Do you really want to do that with List.filter ? It's not its purpose. If you are absolutely certain the head has no duplicate in the list, you could do

List.filter (fun u -> u <> List.hd lst) lst

But note List.tl lst will do it better.