Pop Using Linked List Node in DSA Python - Build from Scratch

Pop Using Linked List Node

📖 Scenario: Imagine you have a stack of books represented as a linked list. You want to remove the top book from the stack safely.

🎯 Goal: You will create a linked list with three nodes, then write code to remove (pop) the top node and print the remaining list.

📋 What You'll Learn

Create a linked list with three nodes containing values 10, 20, and 30 in that order

Create a variable called head pointing to the first node

Write code to remove the first node (pop) by updating head

Print the linked list values after popping the first node

💡 Why This Matters

🌍 Real World

Linked lists are used in many programs to manage collections where items are added or removed frequently, like undo history or browser tabs.

💼 Career

Understanding how to manipulate linked lists is important for software developers working with low-level data structures, memory management, or building efficient algorithms.

1

Create the linked list nodes

Create a class called Node with an __init__ method that takes value and sets self.value and self.next to None. Then create three nodes called node1, node2, and node3 with values 10, 20, and 30 respectively. Link node1.next to node2 and node2.next to node3. Finally, create a variable called head that points to node1.

DSA Python

# Define Node class and create three linked nodes
# Your code here

Hint

Remember to link nodes by setting the next attribute.

2

Prepare to pop the first node

Create a variable called temp and set it equal to head. This will temporarily hold the node to be removed.

DSA Python

class Node:
    def __init__(self, value):
        self.value = value
        self.next = None

node1 = Node(10)
node2 = Node(20)
node3 = Node(30)

node1.next = node2
node2.next = node3

head = node1

# Create temp to hold the node to pop
# Your code here

Hint

Use temp = head to keep track of the node you want to remove.

3

Pop the first node by updating head

Update the variable head to point to the next node after the current head by setting head = head.next. This removes the first node from the linked list.

DSA Python

class Node:
    def __init__(self, value):
        self.value = value
        self.next = None

node1 = Node(10)
node2 = Node(20)
node3 = Node(30)

node1.next = node2
node2.next = node3

head = node1

temp = head

# Update head to remove the first node
# Your code here

Hint

Set head to head.next to remove the first node.

4

Print the linked list after popping

Write a while loop to print the values of the linked list starting from head. Use a variable current initialized to head. In the loop, print current.value followed by ' -> ' if there is a next node, else print 'None'. Move current to current.next each iteration.

DSA Python

class Node:
    def __init__(self, value):
        self.value = value
        self.next = None

node1 = Node(10)
node2 = Node(20)
node3 = Node(30)

node1.next = node2
node2.next = node3

head = node1

temp = head

head = head.next

# Print linked list values after popping
# Your code here

Hint

Use a loop to print each node's value followed by ' -> ', and end with 'None'.