Implementing a Singly Linked List in Python

Introduction

This tutorial delves into the creation and management of a singly linked list in Python. A linked list is a fundamental data structure in computer science, ideal for dynamic data storage.

Step-by-Step Guide

Step 1: Define the Node Class

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

Step 2: Create the LinkedList Class

class LinkedList:
    def __init__(self, value):
        new_node = Node(value)
        self.head = new_node
        self.tail = new_node
        self.length = 1

    def print_list(self):
        temp = self.head
        while temp is not None:
            print(temp.value)
            temp = temp.next

    def make_empty(self):
        self.head = None
        self.tail = None
        self.length = 0

    def append(self, value):
        new_node = Node(value)
        if self.head is None:
            self.head = new_node
            self.tail = new_node
        else:
            self.tail.next = new_node
            self.tail = new_node
        self.length += 1

Step 3: Test the LinkedList

my_linked_list = LinkedList(1)
my_linked_list.make_empty()
my_linked_list.append(1)
my_linked_list.append(2)

print('Head:', my_linked_list.head.value)
print('Tail:', my_linked_list.tail.value)
print('Length:', my_linked_list.length, '\n')
my_linked_list.print_list()

Step 4: Analysis

To determine the output of the provided code, let’s analyze it step by step:

my_linked_list = LinkedList(1): This creates a new LinkedList object with an initial value of 1. The list initially has one node (with value 1), and both the head and tail point to this node. The length is set to 1.
my_linked_list.make_empty(): This method sets the head and tail of the list to None and resets the length to 0. The list is now empty.
my_linked_list.append(1): Appends a new node with value 1 to the list. Since the list is empty, this new node becomes both the head and the tail of the list. The length of the list becomes 1.
my_linked_list.append(2): Appends another node with value 2 to the list. This node is now the new tail of the list, while the head remains unchanged. The length of the list becomes 2.

Now, when the following print statements are executed:

print('Head:', my_linked_list.head.value): This will print the value of the head node, which is 1.
print('Tail:', my_linked_list.tail.value): This will print the value of the tail node, which is 2.
print('Length:', my_linked_list.length, '\n'): This will print the length of the list, which is 2.
my_linked_list.print_list(): This will print the values of the nodes in the list, in this case, 1 and 2.

So, the expected output of the code is:

Head: 1
Tail: 2
Length: 2
1
2

Conclusion

This guide provides a foundational understanding of how to implement a basic singly linked list in Python, including essential methods for list management and traversal.

Summary

Article Name

Implementing a Singly Linked List in Python

Description

Explore the intricacies of implementing a singly linked list in Python with our comprehensive tutorial. Learn how to create, manage, and traverse linked lists through detailed explanations and code examples, perfect for budding programmers and seasoned coders alike.

Author

techtinkerlabs

Publisher Name

TechTinkerLabs Media