在 Ruby 中根据数组中的索引比较项目
我有一个 Card 类，我想重载 > 运算符来与另一张牌进行比较（Ace 高于 King，King 高于 Queen，等等）。我已经忘记了我对 Ruby 知之甚少，也不知道从哪里开始。
class Card
@@RANKS = ['A', 'K', 'Q', 'J', 'T', '9', '8','7','6','5','4','3','2']
attr_reader :rank
def initialize(str)
@rank = str[0,1]
end
def > (other)
#?????
end
end
I have a Card class and I want to overload the > operator to compare against another card (Ace is higher than king, king higher than queen, etc). I've forgotten what little I ever knew about Ruby and don't have a clue where to start.
class Card
@@RANKS = ['A', 'K', 'Q', 'J', 'T', '9', '8','7','6','5','4','3','2']
attr_reader :rank
def initialize(str)
@rank = str[0,1]
end
def > (other)
#?????
end
end
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评论（3）
如果您定义飞船运算符而不是大于，您可能会更高兴。 (<=>)
例如，排序取决于它的定义。
http://ruby-doc.org/ruby-1.9/classes/Enumerable。 html
You might be happier if you define the spaceship operator instead of greater than. (<=>)
Sorting, for instance, depends on it being defined.
http://ruby-doc.org/ruby-1.9/classes/Enumerable.html
我同意达林特的观点。
您所需要做的就是包含 Comparable 并定义 <=>然后您就可以免费进行所有其他比较！为您提供比仅仅定义 '>' 更多的灵活性靠它自己。
用镐书里的话来说：
“Comparable mixin 可用于将比较运算符（<、<=、==、>= 和 >）以及 Between? 方法添加到类中。要实现此目的，Comparable假设任何使用它的类都定义了运算符<=>，因此，作为类编写者，您可以定义一个方法<=>，包括Comparable，并免费获得六个比较函数。”
（免费在线）镐书中提供了完整的示例：
http://ruby-doc.org/docs/ProgrammingRuby/html/ tut_modules.html#S2
（向下滚动几段到“Mixins 给你一种奇妙的控制方式......”）
I would agree with darrint.
All you need do is include Comparable and define <=> and then you will be able to do all the other comparisons for free! Giving you a lot more flexibility than just defining '>' on it's own.
In the words of the pickaxe book:
"The Comparable mixin can be used to add the comparison operators (<, <=, ==, >=, and >), as well as the method between?, to a class. For this to work, Comparable assumes that any class that uses it defines the operator <=>. So, as a class writer, you define the one method, <=>, include Comparable, and get six comparison functions for free."
A full example is available in the (free online) pickaxe book:
http://ruby-doc.org/docs/ProgrammingRuby/html/tut_modules.html#S2
(scroll down a couple of paragraphs to 'Mixins give you a wonderfully controlled way..')
您可以使用
array.index方法。以下代码检查两张卡的索引，如果other卡出现在当前卡之后，则返回true。You can use the
array.indexmethod. The following code checks the index of both cards and returnstrueif theothercard appears after the current card.