Singly Linked List.py

# -*- coding: utf-8 -*-
"""
Created on Tue Apr  7 12:16:45 2020

@author: $parsh
"""
'''DS : Single linked list '''

class node:
    # A wrapper Class        
    def __init__(self,data=None):
        self.data = data
        self.next = None

class linked_list:
    def __init__(self):          
        self.head = node()
    
    def append(self,data):
        new_node = node(data)
        cur = self.head
        while cur.next != None :
            cur = cur.next
        cur.next = new_node
        
    def length(self):
        cur = self.head
        total = 0
        while cur.next !=  None:
            total+=1
            cur = cur.next
        return total
    
    def display(self):
        elems = []
        cur_node = self.head
        while cur_node.next != None:
            cur_node = cur_node.next
            elems.append(cur_node.data)
        print(elems)
    
    def get(self,index) :
        if index>=self.length():
            print ("ERROR : 'Get' Index out of range !")
            return None
        cur_idx = 0
        cur_node = self.head
        while True :
            cur_node = cur_node.next
            if cur_idx==index :
                return cur_node.data
            cur_idx+=1
    
    def erase(self,index) :
        if index>=self.length() :
            print ("ERROR : 'Erase' Index out of range !")
            return None
        cur_idx = 0
        cur_node = self.head
        while True :
            last_node = cur_node
            cur_node = cur_node.next
            if cur_idx ==  index :
                last_node.next = cur_node.next
                return
            cur_idx += 1