python内置函数4-enumerate()

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　　Help on>　　class enumerate(object)
　　|  enumerate(iterable[, start]) -> iterator for index, value of iterable
　　|
　　|  Return an enumerate object.  iterable must be another object that supports
　　|  iteration.  The enumerate object yields pairs containing a count (from
　　|  start, which defaults to zero) and a value yielded by the iterable argument.
　　|  enumerate is useful for obtaining an indexed list:
　　|      (0, seq[0]), (1, seq[1]), (2, seq[2]), ...
　　|
　　|  Methods defined here:
　　|
　　|  __getattribute__(...)
　　|      x.__getattribute__('name') <==> x.name
　　|
　　|  __iter__(...)
　　|      x.__iter__() <==> iter(x)
　　|
　　|  next(...)
　　|      x.next() -> the next value, or raise StopIteration
　　|
　　|  ----------------------------------------------------------------------
　　|  Data and other attributes defined here:
　　|
　　|  __new__ = <built-in method __new__ of type object>
　　|      T.__new__(S, ...) -> a new object with type S, a subtype of T
　　enumerate(sequence, start=0)
　　Return an enumerate object. sequence must be a sequence, an iterator, or some other object which supports iteration. The next() method of the iterator returned by enumerate() returns a tuple containing a count (from start which defaults to 0) and the values obtained from iterating over sequence:
　　>>>
　　>>> seasons = ['Spring', 'Summer', 'Fall', 'Winter']
　　>>> list(enumerate(seasons))
　　[(0, 'Spring'), (1, 'Summer'), (2, 'Fall'), (3, 'Winter')]
　　>>> list(enumerate(seasons, start=1))
　　[(1, 'Spring'), (2, 'Summer'), (3, 'Fall'), (4, 'Winter')]
　　Equivalent to:
　　def enumerate(sequence, start=0):
　　n = start
　　for elem in sequence:
　　yield n, elem
　　n += 1
　　中文说明：
　　用于遍历序列中的元素以及它们的下标,多用于在for循环中得到计数,enumerate参数为可遍历的变量，如 字符串，列表等
　　>>> i=0
　　>>> seq=['one','two','three']
　　>>> for element in seq:
　　...     print i, seq
　　...     i +=1
　　...
　　0 one
　　1 two
　　2 three
　　>>> seq=['one','two','three']
　　>>> for i, element in enumerate(seq):
　　...     print i, seq
　　...
　　0 one
　　1 two
　　2 three
　　>>> for i,j in enumerate('abcdef'):
　　...     print i,j
　　...
　　0 a
　　1 b
　　2 c
　　3 d
　　4 e
　　5 f