ruby 和 codewars 中的类问题答案

【问题标题】：Trouble with classes in ruby and codewarsruby 和 codewars 中的类问题
【发布时间】：2016-04-06 15:58:01
【问题描述】：

所以我在 Codewars: Flexible Card Game 上尝试一个 kata

http://www.codewars.com/kata/5436fdf34e3d6cb156000350/train/ruby

我编写的代码已经通过了大多数测试，但最后却出现了问题：

#draw
chooses cards from the end
Test Passed: Value == [[:clubs, 13]]

removes cards from the deck
Test Passed: Value == 51

returns the cards that were drawn
Test Passed: Value == 1

Expected [:clubs, 13] to be a Card
chooses cards from the end

Test Passed: Value == [[:clubs, 12], [:clubs, 13]]
removes cards from the deck

Test Passed: Value == 50
returns the cards that were drawn

Test Passed: Value == 2
Expected [:clubs, 12] to be a Card
Expected [:clubs, 13] to be a Card

我不明白的是，当测试调用方法 draw 时，它似乎期望来自同一方法的不同返回。我确定这是我做错了什么，但我看不到。任何帮助都会很棒。这是我的代码：

class Card 
 include Comparable
 attr_accessor :suit, :rank
  def initialize(suit, rank)

      @suit = suit
      @rank = rank

  end

  def <=> (another_card)
    if self.rank < another_card.rank
         -1
    elsif self.rank > another_card.rank
          1
    else
          0
    end
  end

  def face_card?
    @rank > 10 ? true : false
  end

  def to_s
    @rank_hash = {13 => "King", 12 => "Queen", 11 => "Jack", 10 => "10", 9 => "9", 8 => "8", 7 => "7", 6 => "6", 5 => "5", 4 => "4", 3 => "3", 2 => "2", 1 => "Ace"}
    @suit_hash = {:clubs => "Clubs", :spades => "Spades", :hearts => "Hearts", :diamonds => "Diamonds"}
    "#{@rank_hash[@rank]} of #{@suit_hash[@suit]}"
  end

end

class Deck < Card
attr_accessor :cards
  def initialize

    @rank_array = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13]
    @suit_array = [:hearts, :diamonds, :spades, :clubs]
    @cards = @suit_array.product(@rank_array)

  end

  def count
    @cards.size
  end

  def shuffle
    @cards.shuffle!
  end

  def draw(n=1)
  @cards.pop(n)
  end

end

【问题讨论】：

What I don't understand is that when the test calls the method draw it seems to expect to different returns from the same method.你能解释一下吗？
首先它调用 draw 并获取：从最后选择卡片测试通过：Value == [[:clubs, 13]] 但在它再次调用它并想要不同的响应之后，这样说：预期[:clubs, 13] 成为卡片从最后选择卡片我现在明白它需要一个 iff 语句但我不知道如何构造它
在to_s 之类的方法中复制@rank_hash 和@suit_hash 之类的数据是非常低效的，并且为该对象的每个实例声明@suit_array 的形式仍然很糟糕。您应该做的是将它们拆分为像 RANK_HASH 这样的常量，因为它们不会改变并且拥有多个副本是没有意义的。
我目前被教导在获得解决方案后进行重构。如果您只是批评形式而不指出错误，那么批评代码似乎毫无意义。我可以在表格工作时修复它。 “你的形式”对我来说没有多大意义，因为我没有你那么先进。感谢您的帮助。
如果您自己解决了问题，请将其作为答案或删除问题。不要让已解决的问题悬而未决。

标签： ruby

【解决方案1】：

问题在于初始化方法。下面解决了这个问题。

def initialize
@cards = []
@rank_array = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13]
@suit_array = [:hearts, :diamonds, :spades, :clubs]
  @suit_array.each do |suit|
    @rank_array.each do |rank|
      each_card = Card.new(suit, rank)
      @cards << each_card
    end
  end
end

【讨论】：