Ruby class instance variable vs. class variable

Instance variable on a class: class Parent @things = [] def self.things @things end def things self.class.things end end class Child < Parent @things = [] end Parent.things << :car Child.things << :doll mom = Parent.new dad = Parent.new p Parent.things #=> [:car] p Child.things #=> [:doll] p mom.things #=> [:car] p dad.things #=> [:car] Class variable: class Parent @@things = [] def self.things @@

[kattton]

Rubyのクラス変数とクラスインスタンス変数の違い。サンプルがとてもわかりやすい。