##### next() - `next( iterator [, default] )` - 返回[[py.迭代器对象|迭代器对象]]下一个项目 - 如果给出`default`，则在迭代器耗尽时返回，否则引发[[py.异常类型|StopIteration]] ```python a = [1,2,3,4] b = iter(a) next(b) # 1 next(b) # 2 next(b) # 3 next(b) # 4 next(b,'None') # None ```