Ruby on Rails Tutorial fourth the ruby behind Rails

Ruby, like other object-oriented languages, uses classes to organize methods, and then instantiate classes to create objects.
1. Construction method
Using double quotation marks is the literal construction method of a string, or you can use the named constructor method, which is called the new method on the class name

>> s = "foobar"
>> s.class
=> String
>> s = String.new ("foobar")
>> s == "foobar"
=> true
>> a = Array.new ([1,2,3])
=> [1,2,3]
>> h = Hash.new
=> {}
>> h [: foo]
=> nil
>> h = Hash.new (0) #The default value is 0
=> {}
>> h [: foo]
=> 0

2. Inheritance of Classes

>> s.class.superclass
=> Object
>> s.class.superclass.superclass
=> BasicObject
>> s.class.superclass.superclass.superclass
=> nil

3, User class Example_user.rb

 
class User
    attr_accessor :anme, :email
    
    def initialize(attributes={})
        @name=attributes[:name]
        @email=attributes[:email]
    end
   
    def formatted_email
        "#{@name} <#{@email}"
    end
end

Ruby on Rails Tutorial fourth the ruby behind Rails