Python实现链表

RT

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( 'empty.')
        
        elif key <0  or key > self.getlength():
            print( ' error')

        else:
            return self.Getitem(key)

    def __setitem__(self, key, value):

        if self.is_empty():
            print ('empty.')
            
        elif key <0  or key > self.getlength():
            print('error')
            
        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 ('empty.')
        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 ('not exist!')

    def insert(self,index,item):

        if self.is_empty() or index<0 or index >self.getlength():
            print ('empty.')
           
        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 ('empty.')
            
        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.')

        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