Python enumerate reverse index only

Question

I am trying to reverse the index given by enumerate whilst retaining the original order of the list being enumerated.

Assume I have the following:

Answer 1

How about using zip instead with a reversed range?

>>> zip(range(9, -1, -1), range(10))
[(9, 0), (8, 1), (7, 2), (6, 3), (5, 4), (4, 5), (3, 6), (2, 7), (1, 8), (0, 9)]


>>> def reversedEnumerate(l):
        return zip(range(len(l)-1, -1, -1), l)
>>> reversedEnumerate(range(10))
[(9, 0), (8, 1), (7, 2), (6, 3), (5, 4), (4, 5), (3, 6), (2, 7), (1, 8), (0, 9)]

As @julienSpronk suggests, use izip to get a generator, also xrange:

import itertools
>>> import itertools
>>> def reversedEnumerate(l):
...     return itertools.izip(xrange(len(l)-1, -1, -1), l)
...     
>>> reversedEnumerate(range(10))

>>> for i in reversedEnumerate(range(10)):
...     print i
...     
(9, 0)
(8, 1)
(7, 2)
(6, 3)
(5, 4)
(4, 5)
(3, 6)
(2, 7)
(1, 8)
(0, 9)