no side effects
Cliff Wells
LogiplexSoftware at earthlink.net
Wed Jan 8 13:37:39 EST 2003
On Wed, 2003-01-08 at 05:10, Michele Simionato wrote:
> I was surprised by the following code:
>
> >>> for i in [1,2,3]:
> ... print i,
> ... i=3
>
> I would have expected only 1 to be printed, but instead Python
> continues the loop without noticing that the value of i has
> changed. IOW, no side effect.
You've gotten a lot of detailed responses, but maybe this will make it
clearer:
_l = [1,2,3]
for _i in range(len(_l)):
i = _l[_i]
print i,
i = 3
In this case you obviously wouldn't expect assigning 3 to i to change
the loop, yet this is similar to what is happening in the case you
presented, except that _i is created implicitly by the interpreter and
is hidden from normal Python programs.
Regards,
--
Cliff Wells, Software Engineer
Logiplex Corporation (www.logiplex.net)
(503) 978-6726 x308 (800) 735-0555 x308
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