How to Create Class in Ruby: Syntax and Examples

In Ruby, you create a class using the class keyword followed by the class name and end. Inside the class, you can define methods and variables to describe its behavior and properties.

Syntax

To create a class in Ruby, use the class keyword, then the class name starting with a capital letter, followed by end. Inside, you can add methods using def and variables.

• class ClassName: Starts the class definition.
• def method_name: Defines a method inside the class.
• end: Ends the method or class definition.

ruby

class ClassName
  def method_name
    # method code
  end
end

Example

This example shows how to create a simple Car class with a method to display its model.

ruby

class Car
  def initialize(model)
    @model = model
  end

  def display_model
    puts "Car model is #{@model}"
  end
end

my_car = Car.new("Toyota")
my_car.display_model

Output

Car model is Toyota

Common Pitfalls

Common mistakes when creating classes in Ruby include:

• Not capitalizing the class name, which is required.
• Forgetting to use end to close class or method definitions.
• Not using @ for instance variables inside methods.

Here is an example of a wrong and right way:

ruby

# Wrong: class name not capitalized and missing @ for instance variable
class car
  def initialize(model)
    @model = model
  end
end

# Right:
class Car
  def initialize(model)
    @model = model
  end
end

Quick Reference

Remember these key points when creating classes in Ruby:

• Class names must start with a capital letter.
• Use def to define methods inside the class.
• Instance variables start with @.
• Close all definitions with end.

Key Takeaways

Use the class keyword with a capitalized name to create a class.

Define methods inside the class using def and close with end.

Instance variables must start with @ to be accessible in methods.

Always close class and method definitions with end.

Capitalization of class names is required in Ruby.