From: Gary Wright <gwtmp01@...>
Date: 2007-02-20T13:51:18+09:00
Subject: Re: How to find out object type


On Feb 19, 2007, at 11:38 PM, Phy Prabab wrote:
> I am curious, is there a way to find out an object type?

You can find out what class gave 'birth' to the object via #class:

[1,2].class   # Array
3.class       # Fixnum

Note that #class does *not* return a string (e.g., "Array") but instead
returns a reference to the actual class object:

a = [1,2].class.new        # allocates a brand new array
p a           # []

It is important to realize that the 'class' of an object is really just
a hint at how an object will respond to methods.  It might be a really
good hint, but a hint nevertheless since objects are free to override
method definitions provided by the class or even to add methods that
the class doesn't provide:

b = [10,20,30]
def b.penultimate
   self[-2]
end
b.penultimate   #  20



Gary Wright