laurenallegra/ruby-objects-class-methods

Ruby Class Methods

Objectives

By the end of this, students should be able to:

• Give an example of a class method you already use.
• Diagram the invocation pattern between #initialize and .new.
• Contrast defining class methods with defining instance methods.
• Contrast invoking class methods with invoking instance methods.

Class Methods

Sometimes a method is associated with a class, not an object.

Observe how a Method on a Class differs from a method on an Instance that Class.

Let's discuss the code below:

class FullCat
  def self.mouse
    puts "I'm in the cats stomach"
  end

  def escape_mouse
    puts 'I escaped the cat'
  end
end

Demonstration

Let's take a look at the code in lib/custom_attr.rb

Lab: Making a Class Method

• Make a class method on Album to search the collection of albums by title.
• Use this class method to set YOUR favorite Album by searching for the album title.
• Create a instance method on songs to add a Rating to Songs.

License

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