英文文档: reversed(seq) Return a reverse iterator. seq must be an object which has a __reversed__() method or supports the sequence protocol (the __len__() method and the __getitem__() method with integer arguments starting at 0). 反转序列生成新的可迭代对象 说明: 1. 函数功能是反转一个序列对象,将其元素从后向前颠倒构建成一个新的迭代器。 >>> a