Python single linked list implementation code instance _python

The definition of a linked list:
A list (linked list) is a data structure consisting of a set of data elements called nodes, each node containing information about the node itself and the address to the next node. Because each node contains address information that can be linked, a variable can be used to access the entire sequence of nodes. That is, a node contains two pieces of information: a value that is used to store data elements, called information fields, and a pointer to the next data element address, called a pointer field. The address of the first node in the list is stored in a single node, called the head node or the first node. The last node in the list has no successor element, and its pointer field is empty.

Python single 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

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
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<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.next = P

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

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)

Results:

5
6
4
40
5
6