Iterate over all pairs of consecutive items in a list
Given a list
l = [1, 7, 3, 5]
I want to iterate over all pairs of consecutive list items
(1,7), (7,3), (3,5), i.e.
for i in xrange(len(l) - 1): x = l[i] y = l[i + 1] # do something
I would like to do this in a more compact way, like
for x, y in someiterator(l): ...
Is there a way to do do this using builtin Python iterators? I'm sure the
itertools module should have a solution, but I just can't figure it out.
Just use zip
>>> l = [1, 7, 3, 5] >>> for first, second in zip(l, l[1:]): ... print first, second ... 1 7 7 3 3 5
As suggested you might consider using the
izip function in
itertools for very long lists where you don't want to create a new list.
import itertools for first, second in itertools.izip(l, l[1:]): ...