1 1.对序列进行分组的函数（摘自web.py源码utils.py文件中）
2 def group(seq, size):
3 """
4 Returns an iterator over a series of lists of length size from iterable.
5
6 >>> list(group([1,2,3,4], 2))
7 [[1, 2], [3, 4]]
8 >>> list(group([1,2,3,4,5], 2))
9 [[1, 2], [3, 4], [5]]
10 """
11 def take(seq, n):
12 for i in xrange(n):
13 yield seq.next() #当seq迭代到最后一个元素直到没有时，抛出StopIteration被外层的list（）捕获
14 if not hasattr(seq, 'next'):
15 seq = iter(seq)
16 while True:
17 inger=take(seq, size)
18 x = list(inger)
19 if x:
20 yield x
21 else:
22 break
