1. reversed 處理的對象是可迭代對象，返回值是一個迭代器，所以可以處理string list 等，如下： PS： list內置__reversed__()方法實現的功能和此類似，使用方法見2 2. reverse reverse是list內置的一個方法，所以只能對list使用，如下： __ ...
1. reversed
class reversed(object)
| reversed(sequence) -> reverse iterator over values of the sequence
|
| Return a reverse iterator
|
| Methods defined here:
|
| __getattribute__(...)
| x.__getattribute__('name') <==> x.name
|
| __iter__(...)
| x.__iter__() <==> iter(x)
|
| __length_hint__(...)
| Private method returning an estimate of len(list(it)).
|
| 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
處理的對象是可迭代對象，返回值是一個迭代器，所以可以處理string list 等，如下：
In [54]: reversed([1,2,3])
Out[54]: <listreverseiterator at 0x7f835810c190>
In [55]: reversed('123')
Out[55]: <reversed at 0x7f835810c2d0>
In [56]: type(reversed('123'))
Out[56]: reversed
In [57]: for i in reversed('123'):
....: print i
....:
3
2
1
PS： list內置__reversed__()方法實現的功能和此類似，使用方法見2
2. reverse
reverse是list內置的一個方法，所以只能對list使用，如下：
In [62]: l = [1, 2, 3] In [63]: l.reverse() In [64]: l Out[64]: [3, 2, 1]
__reversed__()
In [65]: l.__reversed__() Out[65]: <listreverseiterator at 0x7f835810ca90> In [66]: for i in l.__reversed__(): ....: print i ....: 1 2 3
3. 切片
最簡單的一種方法了，可以對string和list使用
In [73]: s Out[73]: 'i am a student.' In [74]: s[::-1] Out[74]: '.tneduts a ma i' In [75]: l Out[75]: [3, 2, 1] In [76]: l[::-1] Out[76]: [1, 2, 3]
