Search for a Value in Linked List in DSA Python - Build from Scratch

Search for a Value in Linked List

📖 Scenario: Imagine you have a list of your favorite books arranged one after another. You want to find if a certain book is in your list.

🎯 Goal: You will create a simple linked list of book names and write code to search for a specific book in that list.

📋 What You'll Learn

Create a linked list with exactly these book names in order: 'Harry Potter', 'The Hobbit', '1984', 'Pride and Prejudice', 'To Kill a Mockingbird'

Create a variable called search_book with the value '1984'

Write a function called search_linked_list that takes the head of the linked list and a book name, and returns True if the book is found, otherwise False

Print Found if the book is in the list, or Not Found if it is not

💡 Why This Matters

🌍 Real World

Linked lists are used in many applications like music playlists, photo galleries, and undo features where items are connected in order.

💼 Career

Understanding linked lists and how to search them is a fundamental skill for software developers working with data structures and algorithms.

1

Create the linked list

Create a class called Node with attributes data and next. Then create the linked list with nodes containing these book names in order: 'Harry Potter', 'The Hobbit', '1984', 'Pride and Prejudice', 'To Kill a Mockingbird'. Assign the first node to a variable called head.

DSA Python

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

Hint

Start by defining the Node class with data and next. Then create each node with the exact book names and link them using the next attribute.

2

Set the book to search for

Create a variable called search_book and set it to the string '1984'.

DSA Python

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

head = Node('Harry Potter')
second = Node('The Hobbit')
third = Node('1984')
fourth = Node('Pride and Prejudice')
fifth = Node('To Kill a Mockingbird')

head.next = second
second.next = third
third.next = fourth
fourth.next = fifth

# Create search_book variable with value '1984'
# Your code here

Hint

Just create a variable named search_book and assign it the string '1984'.

3

Write the search function

Write a function called search_linked_list that takes two parameters: head (the start of the linked list) and target (the book name to find). The function should check each node's data and return True if target is found, otherwise False.

DSA Python

def search_linked_list(head, target):
    current = head
    while current is not None:
        if current.data == target:
            return True
        current = current.next
    return False
# Print 'Found' if search_linked_list returns True, else 'Not Found'

Hint

Use a while loop to go through each node starting from head. Compare current.data with target. Return True if found, else continue. Return False if you reach the end.

4

Print the search result

Use the search_linked_list function with head and search_book. Print 'Found' if the function returns True, otherwise print 'Not Found'.

DSA Python

Hint

Call search_linked_list(head, search_book). Use an if statement to print 'Found' if it returns True, else print 'Not Found'.