[Tutor] Importing question

Alan Gauld alan.gauld at btinternet.com
Fri Jul 13 23:50:35 CEST 2007

"Dick Moores" <rdm at rcblue.com> wrote in 

> import itertools
> def iter_primes():
>     # an iterator of all numbers between 2 and +infinity
>     numbers = itertools.count(2)
> ...

> It works for me in Win XP, Python 2.5.
> However, in trying to dig into the code to understand it, 
> I'm not able to find itertools.py, 

Thats because its a compiled C module not implemented 
in Python. You probably won't find a sys.py either.

If you do

>>> print itertools
<module 'itertools' (built-in)>

You'll see its actually built-in.

So you need to look at the C source to see how it is written!

Alan G

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