python 链表的实现

code

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

class LinkList(object):
    def __init__(self):
        self.head =
    def __getitem__(self, key):
        if self.is_empty():
            print 'linklist is empty.'
            return

        elif key <  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 <  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[])

        p = self.head

        for i in data[:]:
            node = Node(i)
            p.next = node
            node.prev  = p
            p = p.next

    def getlength(self):
        p =  self.head
        length =
        while p!=:
            length+=
            p = p.next

        return length

    def is_empty(self):
        if self.getlength() ==:
            return True
        else:
            return False

    def clear(self):
        self.head = 

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

    def getitem(self,index):
        if self.is_empty():
            print 'Linklist is empty.'
            return
        j =
        p = self.head

        while p.next!= and j <index:
            p = p.next
            j+=

        if j ==index:
            return p.data

        else:

            print 'target is not exist!'

    def insert(self,index,item):
        if self.is_empty() or index< or index >self.getlength():
            print 'Linklist is empty.'
            return

        if index ==:
            q = Node(item,self.head)

            self.head = q

        p = self.head
        post  = self.head
        j =
        while p.next!= and j<index:
            post = p
            p = p.next
            j+=

        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< or index >self.getlength():
            print 'Linklist is empty.'
            return

        if index ==:
            q = Node(item,self.head)

            self.head = q

        p = self.head
        post  = self.head
        j =
        while p.next!= and j<index:
            post = p
            p = p.next
            j+=

        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 =
        while p.next!= and not p.data ==value:
            p = p.next
            i+=

        if p.data == value:
            return i
        else:
            return -

l = LinkList()
l.initlist([,,,,])
print l.getitem()
l.append()
print l.getitem()

l.insert(,)
print l.getitem()
print l.getitem()
print l.getitem()

l.delete()
print l.getitem()

print(l.index())

输出

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