99 Elm 问题/问题 2

问题 2：实现函数 penultimate 以找出列表的倒数第二项。

import Html exposing (text)
import List
import Maybe

penultimate : List a -> Maybe a
-- your implementation goes here
  
main =
  case penultimate (List.range 1 4) of
    Just a -> text (toString a)
    Nothing -> text "No element found"

结果

3

解决方案