python双向链表实现实例代码

示意图:

python双向链表实现代码:

代码如下:

#!/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 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 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