How to Specify Getters and Setters in a Ruby Class?

In a Ruby class, getters/setters can be created for the following:

Instance Variables

There are two ways in which you can define getters and setters for an instance variable in a Ruby class:

  1. Manually Creating Getters and Setters;
  2. Using Accessors to Auto-Generate Getters and Setters.

Manually Creating Getters and Setters:

You can manually create getters and setters for class instance variables in the following way:

class Person
    def initialize(name)
        @name = name

    def name=(name)
        @name = name

    def name

person ="John")

puts # output: "John" = "Bruce"

puts # output: "Bruce"

Using Accessors to Auto-Generate Getters and Setters:

Ruby provides the following accessor methods that automatically generate getter and setter methods for instance variables (negating the need to manually create them):

  1. attr_reader — generates only the getter method;
  2. attr_writer — generates only the setter method;
  3. attr_accessor — generates both, getter and setter methods.

For example, the following would only allow the name and age properties to be read, but not changed:

class Person
    def initialize(name, age)
        @name = name
        @age = age

    attr_reader :name, :age

person ="John", 22)
puts "#{} is #{person.age} years old"

# output: "John is 22 years old"

If you try to set either of the properties it would result in an error:

# ... = "Bruce"

# undefined method `name=' for #<Person:... @name="John", @age=22> (NoMethodError)

Class Variables

To create getter/setter methods for class variables, you must create a class method that returns the value of the class variable:

class Foo
    @@bar = "foobar"


puts #=> "foobar"

It is also possible to access a class variable from a class instance by creating a getter instance method.

This post was published (and was last revised ) by Daniyal Hamid. Daniyal currently works as the Head of Engineering in Germany and has 20+ years of experience in software engineering, design and marketing. Please show your love and support by sharing this post.