python的for如何獲得當前循環次數？
摘自：http://markmail.org/message/ryfven2i75kgsrsm
enumerate是python 2.3中新增的內置函數，它的英文說明爲：
enumerate( iterable)
Return an enumerate object. iterable must be a sequence, an iterator,or some other object which supports iteration. The next() method ofthe iterator returned by enumerate() returns a tuple containing acount (from zero) and the corresponding value obtained from iteratingover iterable. enumerate() is useful for obtaining an indexed series:(0, seq[0]), (1, seq[1]), (2, seq[2]), .... New in version 2.3.它特別適合用於一個for循環時，當我們同時需要計數和元素時可以使用這個函數。舉個簡單的例子，有一個字符串數組，需要一行一行打印出來，同時每行前面加上計數，從1開始。
s = ['abc', 'This is a test', 'Hello, Python']
for i, line in enumerate(s):
print i+1, line