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【进站必读】宝可饭堂社区全局规定v1.10

关于坚决维护同人创作社群秩序与共识的公告

信息: <blockquote data-quote="TAAAAAAA" data-source="post: 2356" data-attributes="member: 2783">Class methods 类方法All methods we’ve seen so far were instance methods, but there’s also a thing called class methods. As the name suggests, these are methods on the class rather than the instance.到目前为止我们说到的所有方法，其实都是实例方法，其实还有另一种类型的方法，叫做类方法。顾名思义，实例方法，就是可以对实例调用的方法。而类方法，就是可以对类本身调用的方法。Where an instance is a creation or version of the class, methods on the class are only accessible on that class and will always be the same. They’re not bound to any instances. An instance would be 10, “hello”, [1,2], 1..5, false, or else; these are versions or instances of the classes, respectively Fixnum, String, Array, Range, and FalseClass, of which you can have as many as you want. As there are no simple examples of class methods by default, we’ll create our own first. You do everything the way you normally would when creating an instance method in a class, but instead of def <MethodName>, you write def self.<MethodName> (or def <ClassName>.<MethodName>, even).那么如何创建类方法呢？很简单，创建类方法和实例方法差不多。首先是位置，你需要在类内部创建类方法，这个和创建实例方法是一样的；接着，创建类方法和实例方法不同的是，你需要在类方法的名字的前面加一个self.，我们来看下面的这个例子：Another way to call class methods (which works only with class methods), is ::say_hello rather than .say_hello on the class.We would use this on CustomClass itself, and not on its instances:我们来看下面的例子：#<CustomClass> means it’s an instance of said class (it usually has a 0x0000 (hex) number after it - ignore this)</blockquote>