Iterating over several lists at once

[Gal Diskin]

On Dec 13, 3:47 pm, "Gal Diskin" <gal.dis... at gmail.com> wrote:
> Hi,
> I am writing a code that needs to iterate over 3 lists at the same
> time, i.e something like this:
>
> for x1 in l1:
>     for x2 in l2:
>         for x3 in l3:
>             print "do something with", x1, x2, x3
>
> What I need to do is go over all n-tuples where the first argument is
> from the first list, the second from the second list, and so on...
>
> I was wondering if one could write this more easily in some manner
> using only 1 for loop.
> What I mean is something like this:
>
> for (x1,x2,x3) in (l1,l2,l3):
>     print "do something with", x1, x2, x3
>
> Or maybe like this:
>
> for x1 in l1, x2 in l2, x3 in l3:
>     print "do something with", x1, x2, x3
>
> However, this code obviously doesn't work...
>
> I'd be very happy to receive ideas about how to do this in one loop and
> with minimal initialization (if at all required).
>
> Thanks in advance,Gal



Sorry for bumping this thread up. I just got back from a vacation and I
had to say thanks to all the people that took the time to answer me.

To Maksim - that's not what I meant, I want to iterate over the
cartesian product of the lists (all ordered tuples, _not_ the tuple
created from the first item in each list, then the tubple created from
the second item in each list... as your example does).

Thanks,
Gal