【Python之旅】第二篇（六）：enumerate枚举

>>> L = ['a', 'b', 'c', 'd']
>>> for i in L:
...   print L.index(i),i
...
0 a
1 b
2 c
3 d

>>> L = ['a', 'b', 'c', 'd']
>>> enumerate(L)
<enumerate object at 0xe83be0>
>>> list(enumerate(L))
[(0, 'a'), (1, 'b'), (2, 'c'), (3, 'd')]
>>> for (i,v) in enumerate(L):
...   print i,v
...
0 a
1 b
2 c
3 d
>>> for (i,v) in list(enumerate(L)):
...   print i,v
...
0 a
1 b
2 c
3 d