List as FIFO in for loop

[rockingred]

On Mar 8, 9:43 am, malkarouri <malkaro... at gmail.com> wrote:
> Hi everyone,
>
> I have an algorithm in which I need to use a loop over a queue on
> which I push values within the loop, sort of:
>
> while not(q.empty()):
>     x = q.get()
>     #process x to get zero or more y's
>     #for each y:
>     q.put(y)
>
> The easiest thing I can do is use a list as a queue and a normal for
> loop:
>
> q = [a, b, c]
>
> for x in q:
>     #process x to get zero or more y's
>     q.append(y)
>
> It makes me feel kind of uncomfortable, though it seems to work. The
> question is: is it guaranteed to work, or does Python expect that you
> wouldn't change the list in the loop?
>
> Regards,
>
> Muhammad Alkarouri

I think it's a bad practice to get into.  Did you intend to do the
"process" step again over the added variables?  If not I would set a
new variable, based on your awful naming convention, let's call it z.
Then use z.append(y) within the for loop and after you are out of your
for loop, q.append(z).