Insert at End Tail Insert in DSA Python - Build from Scratch

Insert at End Tail Insert

📖 Scenario: Imagine you are managing a line of people waiting to buy tickets. Each person is represented as a node in a linked list. When a new person arrives, they join at the end of the line.

🎯 Goal: You will build a simple linked list and write code to insert a new node at the end (tail) of the list. Finally, you will print the list to see the order of people.

📋 What You'll Learn

Create a linked list with three nodes having values 10, 20, and 30

Create a variable called new_node with value 40

Write code to insert new_node at the end of the linked list

Print the linked list values in order separated by ' -> ' and ending with ' -> None'

💡 Why This Matters

🌍 Real World

Linked lists are used in real-world applications like managing playlists, undo functionality in apps, and handling queues where elements are added or removed dynamically.

💼 Career

Understanding linked lists and how to insert nodes is fundamental for software developers, especially when working with data structures that require dynamic memory management.

1

Create the initial linked list

Create a class called Node with attributes data and next. Then create three nodes with values 10, 20, and 30. Link them so that head points to the first node, which links to the second, which links to the third.

DSA Python

# Define Node class and create linked list with nodes 10 -> 20 -> 30
# Your code here

Hint

Remember to link each node's next to the following node.

2

Create the new node to insert

Create a new node called new_node with value 40.

DSA Python

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

head = Node(10)
second = Node(20)
third = Node(30)
head.next = second
second.next = third

# Create new_node with value 40
# Your code here

Hint

Use the Node class to create new_node with data 40.

3

Insert the new node at the end

Write code to insert new_node at the end of the linked list starting from head. Use a variable current to traverse the list until the last node, then set its next to new_node.

DSA Python

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

head = Node(10)
second = Node(20)
third = Node(30)
head.next = second
second.next = third

new_node = Node(40)

# Insert new_node at the end of the list
# Your code here

Hint

Use a while loop to find the last node where next is None.

4

Print the linked list

Write code to print the linked list starting from head. Print each node's data followed by -> . End the print with None.

DSA Python

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

head = Node(10)
second = Node(20)
third = Node(30)
head.next = second
second.next = third

new_node = Node(40)

current = head
while current.next is not None:
    current = current.next
current.next = new_node

# Print the linked list
# Your code here

Hint

Use a while loop to print each node's data followed by ' -> '. After the loop, print 'None'.