Question

I want to create a loop who has this sense:

for i in xrange(0,10):
for k in xrange(0,10):
     z=k+i
     print z

where the output should be

0
2
4
6
8
10
12
14
16
18

Answer 1

You can use zip to turn multiple lists (or iterables) into pairwise* tuples:

>>> for a,b in zip(xrange(10), xrange(10)):
...     print a+b
... 
0
2
4
6
8
10
12
14
16
18

But zip will not scale as well as izip (that sth mentioned) on larger sets. zip‘s advantage is that it is a built-in and you don’t have to import itertools — and whether that is actually an advantage is subjective.

*Not just pairwise, but n-wise. The tuples’ length will be the same as the number of iterables you pass in to zip.