Ruby: kind_of? vs. instance_of? vs. is_a?

📝 Ruby: kind_of? vs. instance_of? vs. is_a?

So, you're diving into the world of Ruby and you've come across these three methods: kind_of?, instance_of?, and is_a?. 😕 You may be scratching your head and wondering, "What's the difference? When should I use which? And why are there so many of them?" 🤔

Well, fear not! I'm here to shed some light on the matter and help you navigate through this confusion. 😎

🤷‍♀️ What's the difference?

Let's start by clarifying the differences between kind_of?, instance_of?, and is_a?. They are all methods that help us check the class type of an object, but there are subtle distinctions you need to be aware of:

• kind_of? and is_a? are aliases and they are interchangeable. They return true if the object is an instance of the specified class or any of its subclasses.

  3.kind_of?(Numeric) # true "hello".is_a?(String) # true

• instance_of? is a bit stricter and returns true only if the object is an instance of the exact specified class and not any of its subclasses.

  3.instance_of?(Numeric) # false "hello".instance_of?(Object) # false

🛠️ Use cases and easy solutions

Now that we know the differences, let's explore when to use each method.

• If you want to check if an object is an instance of a specific class and not any of its subclasses, go for instance_of?.

  class Animal end class Dog < Animal end dog = Dog.new dog.instance_of?(Animal) # false

• On the other hand, if you want to check if an object is an instance of a specific class or any of its subclasses, go for kind_of? or is_a?.

  class Animal end class Dog < Animal end dog = Dog.new dog.kind_of?(Animal) # true dog.is_a?(Animal) # true

✨ Expert tip

You may be wondering why there are multiple methods doing the same thing. Well, the reason for this is because kind_of?, instance_of?, and is_a? are part of Ruby's rich heritage and have slightly different conventions and usages. However, in practice, you'll often see kind_of? and is_a? being used interchangeably.

😍 Engage with us!

Now that you understand the differences between kind_of?, instance_of?, and is_a?, it's time to put your knowledge into action! ✨ Share your thoughts, experiences, and any other questions you may have in the comments section below. We would love to hear from you! Let's dive deeper into Ruby together! 🚀