At this point, one may wonder if all objects are the same. Are the groupings we've already covered - numbers, strings, arrays - supported by the Ruby language?
Ruby does in fact allow one to define groups of objects, or, to use object oriented jargon, classes of objects.
One may look up the class of any object by simply calling the
class method on it. Let's try it out with a few of the
objects we're already familiar with.
As you can see, Ruby tells us what we already suspected - that
1 is a
Fixnum (a special case of Integer),
"" is a
 is an
We can also turn this interrogation around. Here, we'll ask whether an object
is_a? particular class.