[Tutor] Object comparison vs. Identity

[Sheila King]

I recently received one of the Python books I ordered:
Core Python Programming by Wesley Chun

Seems OK. Since I've already programmed in a few different languages, and
worked through the Python tutorial, I'm doing fine with it. It is definitely
not a book for someone who has never programmed before.

Anyhow, to my question...

On pp. 84 - 85 he is discussing object identity, and presents the following
example:
foo1 = 4
foo2 = 3 + 1

He says that the first statement creates a numeric object and assigns it to
foo1. The second statement creates a numeric object, and assigns it to foo2.
Although the value of the two objects are the same, he claims that they are
two distinct objects. 
(I read this as implying, that while 
foo1==foo2 would return 1, 
he is saying that id(foo1) == id(foo2), 
or alternatively foo1 is foo2
would both return 0.)

Now, on my Win98 machine, in an interactive IDLE session, I got the following:

>>> x = 4
>>> y = 3+1
>>> id(x)
8400780
>>> id(y)
8400780
>>> y is x
1
>>> 

I also typed up a similar example, saved it in a file, and ran it from a DOS
prompt, and got the same results. 3+1 did not create a different object for me
than 4.

Is this something I should write to the author about, and let him know there
is an error? Or is there something I'm not picking up on going on here?

--
Sheila King
http://www.thinkspot.net/sheila/
http://www.k12groups.org/