简单的解释，没有任何代码

以上大多数答案都使用代码。这个解释试图通过一个类比/故事来回答这个问题:

外界不能接触CIA内部机密

Let's imagine a really secret place: the CIA. Nobody knows what's happening in the CIA apart from the people inside the CIA. In other words, external people cannot access any information in the CIA. But because it's no good having an organisation that is completely secret, certain information is made available to the outside world - only things that the CIA wants everyone to know about of course: e.g. the Director of the CIA, how environmentally friendly this department is compared to all other government departments etc. Other information: e.g. who are its covert operatives in Iraq or Afghanistan - these types of things will probably remain a secret for the next 150 years. If you're outside the CIA you can only access the information that it has made available to the public. Or to use CIA parlance you can only access information that is "cleared". The information that the CIA wants to make available to the general public outside the CIA are called: attributes.

读写属性的含义:

In the case of the CIA, most attributes are "read only". This means if you are a party external to the CIA, you can ask: "who is the director of the CIA?" and you will get a straight answer. But what you cannot do with "read only" attributes is to make changes changes in the CIA. e.g. you cannot make a phone call and suddenly decide that you want Kim Kardashian to be the Director, or that you want Paris Hilton to be the Commander in Chief. If the attributes gave you "write" access, then you could make changes if you want to, even if you were outside. Otherwise, the only thing you can do is read. In other words accessors allow you to make inquiries, or to make changes, to organisations that otherwise do not let external people in, depending on whether the accessors are read or write accessors.

类中的对象可以很容易地相互访问

另一方面，如果你已经在中央情报局内部，那么你可以很容易地打电话给你在喀布尔的中央情报局特工，因为这些信息很容易获得，因为你已经在里面了。但如果你不在中情局之外，你根本就没有权限:你不能知道他们是谁(读权限)，你也不能改变他们的任务(写权限)。

类也是如此，你可以访问其中的变量、属性和方法。HTH !任何问题，请问，我希望我能澄清。

它只是一个为实例变量定义getter和setter方法的方法。一个示例实现如下:

def self.attr_accessor(*names)
  names.each do |name|
    define_method(name) {instance_variable_get("@#{name}")} # This is the getter
    define_method("#{name}=") {|arg| instance_variable_set("@#{name}", arg)} # This is the setter
  end
end

属性访问器attr_accessor提供了两个免费方法。

就像在Java中，它们被称为getter和setter。

很多答案都给出了很好的例子，所以我就简单点。

# the_attribute

and

# the_attribute =

在旧的ruby文档中，#表示方法。 它还可以包含一个类名前缀… MyClass # my_method

简单地说，它将为类定义setter和getter。

请注意,

attr_reader :v is equivalant to 
def v
  @v
end

attr_writer :v is equivalant to
def v=(value)
  @v=value
end

So

attr_accessor :v which means 
attr_reader :v; attr_writer :v 

等效于为类定义setter和getter。

嗯。很多很好的答案。这是我的一些看法。

attr_accessor是一个简单的方法，可以帮助我们清理(DRY-ing)重复的getter和setter方法。 这样我们就可以更专注于编写业务逻辑而不用担心setter和getter。

简单的解释，没有任何代码

以上大多数答案都使用代码。这个解释试图通过一个类比/故事来回答这个问题:

外界不能接触CIA内部机密

Let's imagine a really secret place: the CIA. Nobody knows what's happening in the CIA apart from the people inside the CIA. In other words, external people cannot access any information in the CIA. But because it's no good having an organisation that is completely secret, certain information is made available to the outside world - only things that the CIA wants everyone to know about of course: e.g. the Director of the CIA, how environmentally friendly this department is compared to all other government departments etc. Other information: e.g. who are its covert operatives in Iraq or Afghanistan - these types of things will probably remain a secret for the next 150 years. If you're outside the CIA you can only access the information that it has made available to the public. Or to use CIA parlance you can only access information that is "cleared". The information that the CIA wants to make available to the general public outside the CIA are called: attributes.

读写属性的含义:

In the case of the CIA, most attributes are "read only". This means if you are a party external to the CIA, you can ask: "who is the director of the CIA?" and you will get a straight answer. But what you cannot do with "read only" attributes is to make changes changes in the CIA. e.g. you cannot make a phone call and suddenly decide that you want Kim Kardashian to be the Director, or that you want Paris Hilton to be the Commander in Chief. If the attributes gave you "write" access, then you could make changes if you want to, even if you were outside. Otherwise, the only thing you can do is read. In other words accessors allow you to make inquiries, or to make changes, to organisations that otherwise do not let external people in, depending on whether the accessors are read or write accessors.

类中的对象可以很容易地相互访问

另一方面，如果你已经在中央情报局内部，那么你可以很容易地打电话给你在喀布尔的中央情报局特工，因为这些信息很容易获得，因为你已经在里面了。但如果你不在中情局之外，你根本就没有权限:你不能知道他们是谁(读权限)，你也不能改变他们的任务(写权限)。

类也是如此，你可以访问其中的变量、属性和方法。HTH !任何问题，请问，我希望我能澄清。