Ruby "is" equivalent

Question

Is there a Ruby equivalent for Python's "is"? It tests whether two objects are identical (i.e. have the same memory location).

Answer 1

Use a.equal? b

http://www.ruby-doc.org/core/classes/Object.html

Unlike ==, the equal? method should never be overridden by subclasses: it is used to determine object identity (that is, a.equal?(b) iff a is the same object as b).

Answer 2

You could also use __id__. This gives you the objects internal ID number, which is always unique. To check if to objects are the same, try

a.__id__ = b.__id__

This is how Ruby's standard library does it as far as I can tell (see group_by and others).