Python program to create and display a doubly linked list

A doubly linked list is a data structure where each node contains data and two pointers - one pointing to the next node and another to the previous node. This allows traversal in both directions.

Node Class Structure

First, we create a Node class that represents individual elements in the doubly linked list ?

class Node:
    def __init__(self, my_data):
        self.prev = None
        self.data = my_data
        self.next = None

Doubly Linked List Implementation

The main class manages the list with head and tail pointers, and provides methods to add data and display the list ?

class Node:
    def __init__(self, my_data):
        self.prev = None
        self.data = my_data
        self.next = None

class DoublyLinkedList:
    def __init__(self):
        self.head = None
        self.tail = None
    
    def add_data(self, my_data):
        new_node = Node(my_data)
        if self.head == None:
            self.head = self.tail = new_node
            self.head.prev = None
            self.tail.next = None
        else:
            self.tail.next = new_node
            new_node.prev = self.tail
            self.tail = new_node
            self.tail.next = None
    
    def print_it(self):
        curr = self.head
        if self.head == None:
            print("The list is empty")
            return
        print("The nodes in the doubly linked list are:")
        while curr != None:
            print(curr.data)
            curr = curr.next

# Create and populate the doubly linked list
my_list = DoublyLinkedList()
print("Elements are being added to the doubly linked list")
my_list.add_data(10)
my_list.add_data(24)
my_list.add_data(54)
my_list.add_data(77)
my_list.add_data(92)
my_list.print_it()

Elements are being added to the doubly linked list
The nodes in the doubly linked list are:
10
24
54
77
92

How It Works

The implementation consists of two main components:

• Node Class: Each node stores data and maintains references to both next and previous nodes
• DoublyLinkedList Class: Manages the list with head and tail pointers for efficient insertion
• add_data() method: Adds new nodes at the end of the list, updating the tail pointer
• print_it() method: Traverses from head to tail, displaying each node's data

Key Features

Conclusion

Doubly linked lists provide bidirectional traversal capabilities through prev and next pointers. The implementation uses a Node class for individual elements and a main class to manage the list structure with head and tail references.