废话不多说，直接贴代码（python 3.6.7)：
#-*-coding=utf-8-*-
class Node(object):
"""结点"""
def __init__(self,item):
self.elem=item
self.next=None
self.prev=None
class DoubleLinkList(object):
"""双链表"""
def __init__(self,node=None):
self.__head = node
def is_empty(self):
"""判断是否为空"""
return self.__head==None
def length(self):
"""链表长度"""
#cur游标，用来移动遍历节点
cur = self.__head
#count记录数量
count=0
while cur!=None:
cur=cur.next
count+=1
return count
def travel(self):
"""遍历整个链表"""
cur=self.__head
while cur!=None:
print(cur.elem)
cur=cur.next
def add(self,item):
"""链表头部添加元素"""
node=Node(item)
node.next=self.__head
self.__head=node
node.next.prev=node
def append(self,item):
"""链表尾部添加元素"""
node=Node(item)
if self.is_empty():
self.__head=node
else:
cur=self.__head
while cur.next!=None:
cur=cur.next
cur.next=node
node.prev=cur
def insert(self,pos,item):
"""指定位置添加元素"""
if pos<=0:
self.add(item)
elif pos>self.length()-1:
self.append(item)
else:
cur=self.__head
count=0
while count<pos:
count+=1
cur=cur.next
node=Node(item)
node.next=cur
node.prev=cur.prev
cur.prev.next=node
cur.prev=node
def remove(self,item):
"""删除节点"""
cur=self.__head
while cur!=None:
if cur.elem==item:
if cur==self.__head:
self.__head=cur.next
if cur.next:
cur.next.prev=None
else:
cur.prev.next=cur.next
cur.next.prev=cur.prev
break
else:
cur=cur.next
def search(self,item):
"""查找节点是否存在"""
cur=self.__head
while cur!=None:
if cur.elem==item:
return True
else:
cur.next
return False
if __name__=="__main__":
dll=DoubleLinkList()
print(dll.is_empty())
print(dll.length())
dll.append(1)
print(dll.is_empty())
print(dll.length())
dll.append(2)
dll.add(8)
dll.append(3)
dll.append(4)
dll.append(5)
dll.append(6)
dll.append(7)
dll.append(8)
dll.travel()
dll.insert(3,100)
dll.travel()
dll.remove(8)
dll.travel()
dll.travel()
dll.remove(100)
dll.insert(100,200)
dll.travel()