"constant sharing" works differently in REPL than in script ?

[shearichard at gmail.com]

Listening to 'Radio Free Python' episode 8 (http://radiofreepython.com/episodes/8/ - around about the 30 minute mark) I heard that Python pre creates some integer constants to avoid a proliferation of objects with the same value.

I was interested in this and so I decided to try it out.

First I did this at the prompt :

>>> c = 1
>>> print id(1)
26906152
>>> print id(c)
26906152
>>> c is 1
True

So that matched what I'd heard and then I did this to test the limits of it :

>>> c = 259
>>> print id(259)
26167488
>>> print id(c)
26167512
>>> c is 259
False

And that was reasonable too as the podcast mentioned it was only done for a small set of integers around zero.

However when I wrote this script :

c = 259
print id(259)
print id(c)
if c is 259:
    print "%s - yes" % (c)
else:
    print "%s - no " % (c)

I got this output :

C:\data\src\Python\foo>python untitled-2.py
26760884
26760884
259 - yes

So what's going on here. The script seems to be sharing objects in a way the REPL isn't ?

Can anyone explain please ?

BTW this is all on : Python 2.6.1 (r261:67517, Dec  4 2008, 16:51:00) [MSC v.1500 32 bit (Intel)] on win32 .