# Check if MyClass extends OtherClass?

**URL:** <https://www.ruby-forum.com/t/check-if-myclass-extends-otherclass/119207>\
**Category:** Ruby\
**Created:** [November 5, 2007, 12:09am UTC](https://www.ruby-forum.com/t/check-if-myclass-extends-otherclass/119207 "2007-11-05T00:09:16Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![josh](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/45deac/32.png) [@josh](https://www.ruby-forum.com/u/josh)\
**Post date:** [November 5, 2007, 12:09am UTC](https://www.ruby-forum.com/t/check-if-myclass-extends-otherclass/119207/1 "2007-11-05T00:09:16Z")

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Hi all

def OtherClass  
end

def MyClass \< OtherClass  
end

How can I check if MyClass extends OtherClass? When I have an instance I  
can call my\_class\_instance.kind\_of?(OtherClass), but what can I call  
when only having the class name?

Thanks  
Josh

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<div class="post-metadata">

**Author:** ![josh](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/45deac/32.png) [@josh](https://www.ruby-forum.com/u/josh)\
**Post date:** [November 5, 2007, 12:21am UTC](https://www.ruby-forum.com/t/check-if-myclass-extends-otherclass/119207/2 "2007-11-05T00:21:18Z")

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Joshua M. wrote:

> How can I check if MyClass extends OtherClass? When I have an instance I  
> can call my\_class\_instance.kind\_of?(OtherClass), but what can I call  
> when only having the class name?

Use the #\< and #\<= methods of classes (and modules):

class OtherClass  
end

class MyClass \< OtherClass  
end

classes = [MyClass, OtherClass]  
classes.each do |c1|  
classes.each do |c2|  
puts “#{c1} \< #{c2}” if c1 \< c2  
puts “#{c1} \<= #{c2}” if c1 \<= c2  
end  
end

**END**

Output:

MyClass \<= MyClass  
MyClass \< OtherClass  
MyClass \<= OtherClass  
OtherClass \<= OtherClass

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<div class="post-metadata">

**Author:** ![josh](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/45deac/32.png) [@josh](https://www.ruby-forum.com/u/josh)\
**Post date:** [November 5, 2007, 12:58am UTC](https://www.ruby-forum.com/t/check-if-myclass-extends-otherclass/119207/3 "2007-11-05T00:58:24Z")

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Thank you very much! So very semantic and easy that I couldn’t have  
guessed it as a veteran PHP programmer… 😉