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Python bidirectional linked list implementation code:
Copy codeThe Code is as follows:
#! /Usr/bin/python
#-*-Coding: UTF-8 -*-
Class Node (object ):
Def _ init _ (self, val, p = 0 ):
Self. data = val
Self. next = p
Self. prev = 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
Node. prev = p
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
Q. prev = p
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. prev = post
Q. next = p
P. prev = q
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
P. next. prev = post
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)
Result;
5
6
4
40
5
6
The result is the same as that of a single-chain table.