Python Linked List: Create a doubly linked list, append some items and iterate through the list

Last update on April 23 2025 12:49:58 (UTC/GMT +8 hours)

8. Doubly Linked List Forward Iteration

Write a Python program to create a doubly linked list, append some items and iterate through the list (print forward).

Sample Solution:

Python Code:

class Node(object):
    # Doubly linked node
    def __init__(self, data=None, next=None, prev=None):
        self.data = data
        self.next = next
        self.prev = prev

class doubly_linked_list(object):
    def __init__(self):
        self.head = None
        self.tail = None
        self.count = 0

    def append_item(self, data):
        # Append an item 
        new_item = Node(data, None, None)
        if self.head is None:
            self.head = new_item
            self.tail = self.head
        else:
            new_item.prev = self.tail
            self.tail.next = new_item
            self.tail = new_item

        self.count += 1

    def print_foward(self):
        for node in self.iter():
            print(node)
            
    def iter(self):
        # Iterate the list
        current = self.head
        while current:
            item_val = current.data
            current = current.next
            yield item_val

items = doubly_linked_list()
items.append_item('PHP')
items.append_item('Python')
items.append_item('C#')
items.append_item('C++')
items.append_item('Java')

print("Items in the Doubly linked list: ")
items.print_foward()

Sample Output:

Items in the Doubly linked list: 
PHP
Python
C#
C++
Java

Flowchart:

For more Practice: Solve these Related Problems:

Write a Python program to create a doubly linked list, append nodes, and iterate from head to tail to display each node’s data.
Write a Python script to build a doubly linked list from an array and print each node’s value along with its previous and next pointers.
Write a Python program to traverse a doubly linked list forward and compute the cumulative sum of node values.
Write a Python function to iterate through a doubly linked list in the forward direction and output the list as a formatted string.

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Next: Write a Python program to create a doubly linked list and print nodes from current position to first node.

Python Code Editor:

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