编译错误，Elixir 中的未定义函数

Question

我正在用 Elixir 制作扑克手牌分析器。该程序接受 52 个整数的输入，并将 5 张奇数（索引）牌分配给玩家 1，5 张偶数（索引）牌分配给玩家 2，然后再决定谁的手牌更好。我为每个玩家做了一个函数（下图）。当我尝试编译时，编译器抛出错误：(CompileError) poker.ex:49: undefined function player1/1。试了很多，好像都失败了，求助！

defmodule Poker do

  decks = %{ 1 => "2C", 2 => "3C", 3 => "4C", 4 => "5C", 5 => "6C", 6 => "7C", 7 => "8C",
    8=> "9C", 9=> "10C", 10 => "11C", 11 => "12C", 12 => "13C", 13 => "1C", 14 => "2D",
    15 => "3D", 16=> "4D", 17 => "5D", 18=> "6D", 19=> "7D", 20=> "8D", 21=> "9D",
    22=> "10D", 23=> "11D", 24=> "12D", 25=> "13D", 26=> "1D", 27=> "2H", 28=> "3H",
    29=> "4H", 30=> "5H", 31=> "6H", 32=> "7H", 33=> "8H", 34=> "9H", 35=> "10H",
    36=> "11H", 37=> "12H", 38=> "13H", 39=> "1H", 40=> "2S", 41=> "3S", 42=> "4S",
    43=> "5S", 44=> "6S", 45=> "7S", 46=> "8S", 47=> "9S", 48=> "10S", 49=> "11S",
    50=> "12S", 51=> "13S", 52=> "1S"}
  defp player1(cards), do: Enum.take(Enum.drop_every(cards, 2), 5)

  defp player2(cards) do
    Enum.take(
      cards -- (Enum.drop_every(cards, 2)) ,5)
  end
  mapHand = for n <- player1(cards), do: Map.get(decks, n)
end

我做错了什么？

Answer 1

您的代码存在一些问题。解决方案主要取决于您想做什么。查看 https://elixir-lang.readthedocs.io/en/latest/technical/scoping.html 以更好地理解 Elixir 中的作用域规则会对您有很大帮助。

对于您的情况，我建议的最直接的解决方案是替换所有匹配项，例如 mapHand = for n <- ... 函数。像这样：

defmodule Poker do                                                                              
  defp decks do
    %{ 1 => "2C", 2 => "3C", 3 => "4C", 4 => "5C", 5 => "6C", 6 => "7C", 7 => "8C",
      8=> "9C", 9=> "10C", 10 => "11C", 11 => "12C", 12 => "13C", 13 => "1C", 14 => "2D",         
      15 => "3D", 16=> "4D", 17 => "5D", 18=> "6D", 19=> "7D", 20=> "8D", 21=> "9D",              
      22=> "10D", 23=> "11D", 24=> "12D", 25=> "13D", 26=> "1D", 27=> "2H", 28=> "3H",            
      29=> "4H", 30=> "5H", 31=> "6H", 32=> "7H", 33=> "8H", 34=> "9H", 35=> "10H",               
      36=> "11H", 37=> "12H", 38=> "13H", 39=> "1H", 40=> "2S", 41=> "3S", 42=> "4S",             
      43=> "5S", 44=> "6S", 45=> "7S", 46=> "8S", 47=> "9S", 48=> "10S", 49=> "11S",              
      50=> "12S", 51=> "13S", 52=> "1S"}                                                          
  end

  defp player1(cards), do: Enum.take(Enum.drop_every(cards, 2), 5)                              

  defp player2(cards) do
    Enum.take(cards -- (Enum.drop_every(cards, 2)), 5)
  end

  def map_hand(cards) do
    for n <- player1(cards), do: Map.get(decks(), n )
  end
end

这样你就可以（在模块之外）做类似的事情：

player_1_cards = [1, 2, 3, 4, 5]
Poker.map_hand(player_1_cards)

然后得到类似的东西：

["3C", "5C"]

编译错误，Elixir 中的未定义函数

Compilation error, undefined function in Elixir

compilation

elixir