99 道 Elm 难题/问题 3

问题 3：实现函数 nth，以返回列表的第 n 个元素。

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"

结果

3

解答