以下程序是实现链表的一些简单操作：

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 __set__(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

    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>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>self.getlength():
            print 'link 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.delete(2)
print l.getitem(4)