如何使用遍历双向链表并跳过空节点的迭代器

Question

由于双链表有两个虚拟节点，一个是头部，另一个是尾部。我可以通过self跳过伪尾节点__current==None:raise StopIteration，但我不知道如何传递虚拟头节点并继续遍历以下节点。

class LinkedListDLL:

    def __init__(self):
        self.__head = NodeDLL(None)
        self.__head.set_next(self.__head)
        self.__head.set_prev(self.__head)
        self.__count = 0

    def size(self):
        return self.__count;

    def is_empty(self):
        return self.__count == 0

    def add_before(self, item, curr):
        new_node = NodeDLL(item)
        new_node.set_next(curr)
        new_node.set_prev(curr.get_prev())
        curr.set_prev(new_node)
        new_node.get_prev().set_next(new_node)
        self.__count += 1

    def add_to_head(self, item):
        self.add_before(item, self.__head.get_next())

    def add_to_tail(self, item):
        self.add_before(item, self.__head)

    def remove_from_head(self):
        self.remove(self.__head.get_next())

    def remove_from_tail(self):
        self.remove(self.__head.get_prev())

    def remove(self, curr):
        curr.get_prev().set_next(curr.get_next())
        curr.get_next().set_prev(curr.get_prev())
        self.__count -= 1

    def __iter__(self):
        return LinkedListIterator(self.__head)

class LinkedListIterator:
    def __init__(self, head):
        self.__current = head

    def __next__(self):
        if self.__current == None :
            raise StopIteration
        else:
            item = self.__current.set_data.get_next()
            self.__current = self.__current.get_next()
            return item

Answer 1

您应该重构代码，记住nodedell（None）可能与None不同。完成后：

def __next__(self):
    if not self.__current.get_next():
        raise StopIteration
    #Skips first value in list, i.e. head
    self.__current = self.__current.get_next()
    return self.__current