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python单链表实现代码实例

发布时间：2024-04-28 00:04:33 来源：互联网

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初夏的脚步刚刚走来，人们纷纷把厚重的单衣脱掉，换上了凉爽的短袖，又把旅游鞋换成了颜色各不相同的夹鞋，有淡绿色的；有洁白的；还有深蓝色的……

链表的定义：
链表(linked list)是由一组被称为结点的数据元素组成的数据结构，每个结点都包含结点本身的信息和指向下一个结点的地址。由于每个结点都包含了可以链接起来的地址信息，所以用一个变量就能够访问整个结点序列。也就是说，结点包含两部分信息：一部分用于存储数据元素的值，称为信息域；另一部分用于存储下一个数据元素地址的指针，称为指针域。链表中的第一个结点的地址存储在一个单独的结点中，称为头结点或首结点。链表中的最后一个结点没有后继元素，其指针域为空。　　

python单链表实现代码：


#!/usr/bin/python
# -*- coding: utf-8 -*-
class Node(object):
 def __init__(self,val,p=0):
 self.data = val
 self.next = p
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
 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

 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.next = p

 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
 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)