Pairwise circular Python 'for' loop

Question

Is there a nice Pythonic way to loop over a list, retuning a pair of elements? The last element should be paired with the first.

So for instance, if I have the list

Answer 1

I'd use a slight modification to the pairwise recipe from the itertools documentation:

def pairwise_circle(iterable):
    "s -> (s0,s1), (s1,s2), (s2, s3), ... (s,s0)"
    a, b = itertools.tee(iterable)
    first_value = next(b, None)
    return itertools.zip_longest(a, b,fillvalue=first_value)

This will simply keep a reference to the first value and when the second iterator is exhausted, zip_longest will fill the last place with the first value.

(Also note that it works with iterators like generators as well as iterables like lists/tuples.)

Note that @Barry's solution is very similar to this but a bit easier to understand in my opinion and easier to extend beyond one element.