the term

About various variables and method terms. The shortage of scope information will be added later. (I'm tired of organizing and writing in my head ...: joy :) If you have any strange points or points you notice, Sorry to trouble you, but I would appreciate your guidance and suggestions: hand_splayed_tone2:

class A #A class(Normal class)
  @@class_variable = "Class variables"

  # @class_instance_variable = "Class instance variable"
  # =>If declared here, it is considered a "class instance variable" rather than an "instance variable".
  #Same prefix as "instance variable"(@〜)。

  def initialize #Instance method
    @instance_variable = "Instance variables"
    puts "#{@instance_variable} at initialize"
  end

  def hoge #Instance method
    puts "#{@instance_variable} at xxx"
  end

  def self.fuga #Class method(Definition method: Singular method method)
    puts "#{@instance_variable} at yyy"
  end

  class << self #Singularity class
    def fuga #Class method(Definition method: Singular class method)
      puts "#{@instance_variable} at yyy"
    end
  end
end

#It can be accessed from the instance method initialize
instance = A.new # => "Instance variable at initialize" #Instance generation

instance.hoge #Instance method call
#Instance variables can also be used with other instance methods
instance.hoge # => 'Instance variable at xxx'

A.new.hoge #Instance method call(name of the class.new.Instance method name)
A.new.hoge # => 'Instance variable at xxx'

A.fuga #Class method call
#Instance variables from class methods(@〜)Cannot be used
A.fuga # => nil

Reference article

:relaxed: @ mogulla3

https://qiita.com/mogulla3/items/cd4d6e188c34c6819709 @tbpgr
https://qiita.com/tbpgr/items/56eb65c0ea5882abbb07

[Self-use memo] (Ruby) class, class instance, instance

the term

Reference article