Python bidirectional linked list implementation instance code _python

Diagram:

python bidirectional linked list implementation code :

Copy Code code 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)

The result is;

5
6
4
40
5
6

Same as the single linked list results.