Python技巧(enumerate)
>>> i = 0>>> seq = ['one', 'two', 'three']
>>> for element in seq:
... seq = '%d: %s' % (i, seq)
... i += 1
...
>>> seq
['0: one', '1: two', '2: three']
>>> seq = ['one', 'two', 'three']
>>> for i, element in enumerate(seq):
... seq = '%d: %s' % (i, seq)
...
>>> seq
['0: one', '1: two', '2: three']
>>> def _treatment(pos, element):
... return '%d: %s' %(pos, element)
...
>>> seq = ['one', 'two', 'three']
>>>
['0: one', '1: two', '2: three']
最后一种方式更容易矢量化，因为它共享了基于序列中单个项目的小函数。
每当要对序列中的内容进行循环处理时，就应该尝试用List comprehensions来代替它。
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