# Re: How to find out object type

**URL:** <https://www.ruby-forum.com/t/re-how-to-find-out-object-type/86136>\
**Category:** Ruby\
**Created:** [February 20, 2007, 5:56am UTC](https://www.ruby-forum.com/t/re-how-to-find-out-object-type/86136 "2007-02-20T05:56:32Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Phy\_P](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/a587f6/32.png) [@Phy\_P](https://www.ruby-forum.com/u/Phy_P)\
**Post date:** [February 20, 2007, 5:56am UTC](https://www.ruby-forum.com/t/re-how-to-find-out-object-type/86136/1 "2007-02-20T05:56:32Z")

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umm, perhaps I am doing something wrong:

irb(main):005:0\> o.kind\_of(0)  
NoMethodError: undefined method `kind_of' for 123:Fixnum from (irb):5 irb(main):006:0> o.kind_of(1) NoMethodError: undefined method `kind\_of’ for 123:Fixnum  
from (irb):6  
irb(main):007:0\>

----- Original Message ----  
From: Daniel N [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
To: ruby-talk ML [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
Sent: Monday, February 19, 2007 8:43:17 PM  
Subject: Re: How to find out object type

object.kind\_of?( Array ) #=\> To test if it is something  
object.is\_a?( Array ) #=\> Same

object.class #=\> Tells you what class the object thinks it is.

---

<div class="post-metadata">

**Author:** ![Phy\_P](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/a587f6/32.png) [@Phy\_P](https://www.ruby-forum.com/u/Phy_P)\
**Post date:** [February 20, 2007, 6:02am UTC](https://www.ruby-forum.com/t/re-how-to-find-out-object-type/86136/2 "2007-02-20T06:02:32Z")

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On 2/20/07, Phy P. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> umm, perhaps I am doing something wrong:
> 
> irb(main):005:0\> o.kind\_of(0)  
> NoMethodError: undefined method `kind_of' for 123:Fixnum from (irb):5 irb(main):006:0> o.kind_of(1) NoMethodError: undefined method `kind\_of’ for 123:Fixnum  
> from (irb):6  
> irb(main):007:0\>

methods may have punctuation in ruby. kind\_of?( OBJECT ) uses a  
question  
mark.

It makes it into a question. Effectively what happens as I understand  
it is  
you ask the object what kind of object are you?

eg

o.kind\_of?( Fixnum )