99 道 Elm 難題/問題 3

問題 3：實現函式 nth，以返回列表的第 n 個元素。

import Html exposing (text)
import List exposing (head, length)
import Maybe

nth: Int -> List a -> Maybe a
-- your implementation goes here

main =
  case (nth 2 (List.range 1 4)) of
    Just a -> text (toString a)
    Nothing -> text "No element found"

結果

3

解答