Python List Operation instance, python list instance

Python List Operation instance, python list instance

This article describes how to operate python lists. Share it with you for your reference.

The specific implementation method is as follows:

Copy codeThe Code is as follows: class Node:
"Single node in a data structure """
 
Def _ init _ (self, data ):
"Node constructor """

Self. _ data = data
Self. _ nextNode = None

Def _ str _ (self ):
"Node data representation """
 
Return str (self. _ data)
 
Class List:
"Linked list """
 
Def _ init _ (self ):
"List constructor """
 
Self. _ firstNode = None
Self. _ lastNode = None
 
Def _ str _ (self ):
"" List string representation """
 
If self. isEmpty ():
Return "empty"
 
CurrentNode = self. _ firstNode
Output = []
 
While currentNode is not None:
Output. append (str (currentNode. _ data ))
CurrentNode = currentNode. _ nextNode
 
Return "". join (output)
 
Def insertAtFront (self, value ):
"Insert node at front of list """
 
NewNode = Node (value)
 
If self. isEmpty (): # List is empty
Self. _ firstNode = self. _ lastNode = newNode
Else: # List is not empty
NewNode. _ nextNode = self. _ firstNode
Self. _ firstNode = newNode

Def insertAtBack (self, value ):
"Insert node at back of list """
 
NewNode = Node (value)
 
If self. isEmpty (): # List is empty
Self. _ firstNode = self. _ lastNode = newNode
Else: # List is not empty
Self. _ lastNode. _ nextNode = newNode
Self. _ lastNode = newNode
 
Def removeFromFront (self ):
"Delete node from front of list """
 
If self. isEmpty (): # raise exception on empty list
Raise IndexError, "remove from empty list"
 
TempNode = self. _ firstNode
 
If self. _ firstNode is self. _ lastNode: # one node in list
Self. _ firstNode = self. _ lastNode = None
Else:
Self. _ firstNode = self. _ firstNode. _ nextNode
 
Return tempNode
 
Def removeFromBack (self ):
"Delete node from back of list """
 
If self. isEmpty (): # raise exception on empty list
Raise IndexError, "remove from empty list"

TempNode = self. _ lastNode
 
If self. _ firstNode is self. _ lastNode: # one node in list
Self. _ firstNode = self. _ lastNode = None
Else:
CurrentNode = self. _ firstNode
 
# Locate second-to-last node
While currentNode. _ nextNode is not self. _ lastNode:
CurrentNode = currentNode. _ nextNode

CurrentNode. _ nextNode = None
Self. _ lastNode = currentNode
 
Return tempNode

Def isEmpty (self ):
"Returns true if List is empty """
 
Return self. _ firstNode is None

I hope this article will help you with Python programming.