what is a class method? in ruby

In Ruby, a class method is a method that is defined on the class itself rather than on instances of the class. These methods can be called directly on the class without the need to create an instance of the class. Class methods are useful when you want to define behavior that applies to the class as a whole rather than to individual instances.

To define a class method in Ruby, you can use the self keyword followed by the method name. Here's an example:

main.rb
class MyClass
  def self.my_class_method
    puts "This is a class method"
  end
end

# Calling the class method
MyClass.my_class_method
137 chars
9 lines

In the example above, my_class_method is a class method defined on the MyClass class. It can be called directly on the class itself without the need to create an instance of MyClass.

The output of the above code will be:

main.rb
This is a class method
23 chars
2 lines

When defining a class method, the self keyword refers to the class object itself. This allows you to access class-level variables and methods within the class method.

Note that class methods in Ruby are different from instance methods, which are defined on instances of a class and can only be called on those instances.

Class methods are commonly used in Ruby for utility methods, factory methods, or methods that perform operations on class-level data.

Overall, class methods provide a way to define behavior that is specific to the class itself rather than to individual instances of the class.