Python Linked List: Create a doubly linked list and print nodes from current position to first node

Last update on April 01 2025 13:17:02 (UTC/GMT +8 hours)

9. Doubly Linked List Backward from Current

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

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 print_backward(self):
        current = self.tail
        while current:
            print(current.data)
            current = current.prev
            
    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("Print Items in the Doubly linked backwards:")
items.print_backward()

Sample Output:

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

Flowchart:

For more Practice: Solve these Related Problems:

• Write a Python program to set a pointer to a middle node in a doubly linked list and then iterate backward to the head, printing each node.
• Write a Python script to traverse a doubly linked list in reverse starting from a given node and count the nodes encountered.
• Write a Python program to implement a function that, given a node, prints all preceding node values in reverse order using the previous pointers.
• Write a Python function to start from a specified node in a doubly linked list and traverse backward, outputting the reversed sequence as a list.

Python Code Editor:

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