Question

代码：

open Hashtbl;;

type 'a option = None | Some of 'a;;

let ht = create 0;;

let rec charCount fd =
  let x = 
    try Some (input_char fd)
    with End_of_file -> None
  in
  match x with
  | Some c -> 
    let v = 
      try find ht c
      with Not_found -> 0
    in
    replace ht c (v+1);
    charCount fd
  | None -> ();;

let loadHisto fn = 
  let fd = open_in fn in 
    charCount fd;;

let rec printList l = match l with
  | [] -> print_newline ()
  | h::t -> print_char h; print_string " "; printList t;;

let hashtbl_keys h = Hashtbl.fold (fun key _ l -> key :: l) h [];;
let compare_function a b = compare (find ht b) (find ht a);;
let akeys = List.sort compare_function (hashtbl_keys ht);;

printList (List.sort compare_function (hashtbl_keys ht));;
printList akeys;;

结果：

ocaml histo.ml
  e t s u a i n p j (*here is the first printList*)
(*and here should be the second one, but there is only a blank*)

问题在于：我对列表进行了排序，并尝试显示它的内容，但正如您所看到的，似乎我不能为我的结果列表命名

编辑：我不认为这是一个缓冲问题，因为即使我只打印akeys，也没有什么

编辑：我添加了下面要求的代码并且ht是一个hashtbl，它包含它应包含的内容（我检查了这个）

Ocaml不会让我命名我的名单

0 个答案: