使用 zip 代替反向范围怎么样?
>>> 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)]
正如@julienSpronk建议的那样,使用izip
也获得发电机xrange
:
import itertools
>>> import itertools
>>> def reversedEnumerate(l):
... return itertools.izip(xrange(len(l)-1, -1, -1), l)
...
>>> reversedEnumerate(range(10))
<itertools.izip object at 0x03749760>
>>> 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)