Classes and Objects

Ruby is a fully object-oriented language, meaning everything in Ruby is an object.

In this lesson, you will learn how to define classes, create objects, and instantiate new instances of a class.

Defining a Class

Classes are defined using the class keyword.

class Person
end

Creating an Object

You can create an instance of a class using the new method.

class Person
end

person1 = Person.new
puts person1.class

Using Initialize Method

The initialize method runs when an object is created.

class Person
  def initialize(name)
    @name = name
  end
end

person1 = Person.new('Alice')

Calling Methods on an Object

You can define and call methods inside a class.

class Person
  def say_hello
    puts 'Hello!'
  end
end

person1 = Person.new
person1.say_hello

Instance Variables

Instance variables store object-specific data and start with @.

class Person
  def initialize(name)
    @name = name
  end
  
  def show_name
    puts @name
  end
end

person1 = Person.new('Alice')
person1.show_name

Instance Methods

Instance methods allow objects to interact with their own data.

class Person
  def initialize(name)
    @name = name
  end
  
  def greet
    puts "Hello, my name is #{@name}!"
  end
end

person1 = Person.new('Alice')
person1.greet

Accessing Instance Variables

Use getter and setter methods to access instance variables.

class Person
  attr_accessor :name
end

person1 = Person.new
person1.name = 'Alice'
puts person1.name

Congratulations!

You have learned how to define classes and create objects in Ruby.

Next, you will explore instance variables and methods in more detail.