Python单链表实现

# -*- coding:utf-8 -*-
#创建单个节点类
class Node:
    def __init__(self, x):
        self.val = x
        self.next = None
'''链表类
添加一个哨兵节点，便于后面的操作
函数实现：增删改查
'''
class LinkList(object):

    def __init__(self):
        self.head = None

    def init(self,data):
    #初始化哨兵节点
        self.head = Node(None)
        p = self.head
        for i in data:
            node = Node(i)
            p.next = node
            p = p.next

    def get_length(self):
        p = self.head
        length = 0
        while p.next:
            length+=1
            p = p.next
        return length

    '''在第几个节点的位置进行插入，从1开始，0代表头结点'''
    def insert(self,index,item):
        #如果插入位置大于链表长度,或者index<0，无法插入
        if index > self.get_length() or index < 0:
            print('LinkList is null!')
        if index==0:
            self.head.next = Node(item)
        #找到插入位置
        insert_location = 0
        p = self.head.next
        q = Node(item)#待插入数据
        while p:
            insert_location+=1
            if insert_location==index:
                q.next = p.next
                p.next = q
            else:
                p = p.next

    '''删除第几个节点，索引从1开始'''
    def delete(self,index):
        pre = self.head
        p = self.head.next
        j=0
        while p:
            j+=1
            if j ==index:
                pre.next = p.next
            pre = pre.next
            p = p.next

    def find(self,value):
        index = 0 #节点索引，从1开始，不包含哨兵节点
        p = self.head.next
        while p:
            index+=1
            if p.val == value:
                return index
            p = p.next

    def print_LinkList(self):
        p = self.head.next
        while p:
            print(p.val,end='-->')
            p = p.next
        prin('NULL')
        print('\n')

a = LinkList()
a.init([1,2,3])
a.insert(2,10)
a.print_LinkList()
a.delete(1)
a.print_LinkList()
print(a.find(10))
print(a.get_length())