python 双向链表

##################### 定义双向链表结点 ##########################
class Node(object):
    '''双向链表结点'''

    def __init__(self,item):
        self.item = item
        # 指向上一个结点
        self.prev = None
        # 指向下一个结点
        self.next = None
        
##################### 定义双向链表
class Node(object):
    '''双向链表结点'''

    def __init__(self,item):
        self.item = item
        # 指向上一个结点
        self.prev = None
        # 指向下一个结点
        self.next = None


# 是否为空校验装饰器
def func(funct):
    # from functools import wraps
    # @wraps(funct)
    def war(self, *args, **kwargs):
        if self.is_empty():
            print(self.is_empty())
            return '链表为空！'
        res = funct(self,*args,**kwargs)
        return res
    return war

class BilateralLinkList(object):
    '''双向链表'''

    def __init__(self):
        self._head = None



    def is_empty(self):
        '''判断链表是否为空'''
        if self._head is None:
            return True

    @func
    def length(self):
        '''获取链表得长度'''
        cur = self._head
        count = 0
        while cur.next != self._head:
            count += 1
            cur = cur.next
        return count

    @func
    def items(self):
        '''遍历链表'''
        cur = self._head
        while cur.next is not None:
            yield cur.item
            cur = cur.next
        yield cur.item


    def add(self,item):
        '''给链表头插入数据'''
        node = Node(item)
        cur = self._head
        if self.is_empty():
            self._head = node
        else:
            node.next = self._head
            self._head.prev = node
            self._head = node

    @func
    def append(self,item):
        '''给双向链表尾部添加元素'''
        node = Node(item)
        cur = self._head
        while cur.next is None and cur.prev is not None:
            cur.next = node
            node.prev = cur

    @func
    def insert(self,index,item):
        '''给指定位置插入值'''
        node = Node(item)
        cur = self._head
        pre = None
        if cur.next is None and cur.prev is None:
            # 此时给头部插入值
            self.add(item)
        elif cur.next is None and cur.prev is not None:
            # 此时给尾部添加值
            self.append(item)
        else:
            for i in range(index - 1):
                cur = cur.next
            node.prev = cur
            node.next = cur.next.next
            cur.next = node

    @func
    def remove(self,item):
        '''删除链表的值'''
        cur = self._head
        pre = None
        if cur.item == item:
            if cur.next is None:
                self._head = None
                return
            else:
                cur = cur.next
                cur.prev = None
                self._head = cur
                return
        while True:
            if cur.item == item:
                if cur.next is None:
                    cur.prev = None
                    pre.next = None
                    return
                else:
                    pre.next = cur.next
                    cur.next.prev = pre
                    return
            else:
                pre = cur
                cur = cur.next

    @func
    def find(self,item):
        return item in self.items()

if __name__ == '__main__':
    dd = BilateralLinkList()
    for i in range(6):
        dd.add(i)
    dd.add('qwe1')
    dd.remove(0)
    dd.remove(5)
    print(list(dd.items()))
    print(dd.find(3))