python双向链表实现实例代码

示意图：

python双向链表实现代码：

#!/usr/bin/python
# -*- coding: utf-8 -*-

class Node(object):
 def __init__(self,val,p=0):
 self.data = val
 self.next = p
 self.prev = p
class LinkList(object):
 def __init__(self):
 self.head = 0
 def __getitem__(self, key):
 if self.is_empty():
 print 'linklist is empty.'
 return
 elif key <0 or key > self.getlength():
 print 'the given key is error'
 return
 else:
 return self.getitem(key)

 def __setitem__(self, key, value):
 if self.is_empty():
 print 'linklist is empty.'
 return
 elif key <0 or key > self.getlength():
 print 'the given key is error'
 return
 else:
 self.delete(key)
 return self.insert(key)
 def initlist(self,data):
 self.head = Node(data[0])
 p = self.head
 for i in data[1:]:
 node = Node(i)
 p.next = node
 node.prev = p
 p = p.next
 def getlength(self):
 p = self.head
 length = 0
 while p!=0:
 length+=1
 p = p.next
 return length
 def is_empty(self):
 if self.getlength() ==0:
 return True
 else:
 return False
 def clear(self):
 self.head = 0

 def append(self,item):
 q = Node(item)
 if self.head ==0:
 self.head = q
 else:
 p = self.head
 while p.next!=0:
 p = p.next
 p.next = q
 q.prev = p

 def getitem(self,index):
 if self.is_empty():
 print 'Linklist is empty.'
 return
 j = 0
 p = self.head
 while p.next!=0 and j <index:
 p = p.next
 j+=1
 if j ==index:
 return p.data
 else:
 print 'target is not exist!'
 def insert(self,index,item):
 if self.is_empty() or index<0 or index >self.getlength():
 print 'Linklist is empty.'
 return
 if index ==0:
 q = Node(item,self.head)
 self.head = q
 p = self.head
 post = self.head
 j = 0
 while p.next!=0 and j<index:
 post = p
 p = p.next
 j+=1
 if index ==j:
 q = Node(item,p)
 post.next = q
 q.prev = post
 q.next = p
 p.prev = q

 def delete(self,index):
 if self.is_empty() or index<0 or index >self.getlength():
 print 'Linklist is empty.'
 return
 if index ==0:
 q = Node(item,self.head)
 self.head = q
 p = self.head
 post = self.head
 j = 0
 while p.next!=0 and j<index:
 post = p
 p = p.next
 j+=1
 if index ==j:
 post.next = p.next
 p.next.prev = post
 def index(self,value):
 if self.is_empty():
 print 'Linklist is empty.'
 return
 p = self.head
 i = 0
 while p.next!=0 and not p.data ==value:
 p = p.next
 i+=1
 if p.data == value:
 return i
 else:
 return -1

l = LinkList()
l.initlist([1,2,3,4,5])
print l.getitem(4)
l.append(6)
print l.getitem(5)
l.insert(4,40)
print l.getitem(3)
print l.getitem(4)
print l.getitem(5)
l.delete(5)
print l.getitem(5)
l.index(5)

结果为；

5
6
4
40
5
6

和单链表结果一样。

到此这篇关于python双向链表实现实例代码就介绍到这了。做人聪不聪明其实不重要，甚至情商不高也没关系，但一定得够大气。做人线条粗一点不是坏事，千万不要几句嘲讽就让你垂头丧气、一点打击就让你万念俱灰。人生永远是这个道理：在意的越多，遇到的麻烦就会越多。什么都不在乎的人，反倒一点麻烦都没有。更多相关python双向链表实现实例代码内容请查看相关栏目，小编编辑不易，再次感谢大家的支持！