Great Article. Very useful

Good article. Thank You for explanation on nil value. Good to know it is an singleton.

huhu Thanks Brother, helpful

Rubyist-

thanks for the insight !! these do help ~

2016 and your article is still helping people...thanks!

So.... 1.object_id = 3
and 2.object_id = 5
3.object_id = 7

Bring my shotgun im gonna shoot this logic.

Very well explained. I am wondering if Ruby has got the similar way where null is handled with Optional in Scala and Java 8

Very helpful - thanks!

This ruby n00b found this article helpful. Thank you.

Hey, great article. Thanks for mentioning how `Fixnum` ids are just the left-shift-plus-one of the value they represent. That's super cool. It raises an important question for a Ruby learner like myself: are `Fixnum`s actual objects, or are they just pseudo-objects?

This was really helpful. Thanks for taking the time to explain.

Well done, your articles are really clear and useful!

Hey,

Learning Ruby right now, your article helped me out.
Thanks!

No, this does not work.

Calling:
if my_object.nil?

If my_object is null results in an error.

> No, this does not work.

> Calling:
> if my_object.nil?

> If my_object is null results in an error.

It does work, but only for objects being **potentially** nil. That is, a reference has to exist.

Calling `nil?` on an existing variable will always work, though calling this (or any other) method on an undefined variable causes the `NameError` to be raised.

To achieve what you wanted to achieve, you can call `defined?`:

> defined? my_object
=> nil

> my_object = 1
> defined? my_object
=> "local-variable"

> my_object = nil
> defined? my_object
=> "local-variable"
> my_object.nil?
=> true

Really clear and thorough explanation, thanks.

So you're saying that I should always write:
`if x.object_id == 4`
when I want to see if x is nil, then?

Just kidding.

Why didn't you use the "unless" version?

Just for the sake of readability; I think that "if my_object.nil?" is much more clearer in this case. I usually use the "unless" keyword in this way:

raise NotFound unless @post

Should be:

unless my_object.nil?
my_object.display_info()
else
puts "There is no object!"
end

Of course there was a mistake... I've already fixed it, many thanks!