Use cases for each method type in Python - Mini Project: Build & Apply

Use Cases for Each Method Type

📖 Scenario: Imagine you are creating a simple program to manage a library's book collection. You want to organize your code using different types of methods to see when each type is useful.

🎯 Goal: Build a Python class Book that uses instance methods, class methods, and static methods to handle book details, count books, and check if a book title is valid.

📋 What You'll Learn

Create a class called Book

Use an instance method to display book details

Use a class method to count how many books have been created

Use a static method to check if a book title is valid (non-empty string)

Create at least two Book objects

💡 Why This Matters

🌍 Real World

Using different method types helps organize code clearly in real applications like managing libraries, users, or products.

💼 Career

Understanding method types is essential for writing clean, maintainable object-oriented code in software development jobs.

1

Create the Book class with instance variables

Create a class called Book with an __init__ method that takes title and author as parameters and stores them as instance variables.

Python

class Book:
    def __init__(self, title, author):
        # Your code here

Need a hint?

Use self.title = title and self.author = author inside the __init__ method.

2

Add a class variable and class method to count books

Add a class variable called count initialized to 0. Increase count by 1 inside the __init__ method. Then add a class method called get_count that returns the current value of count. Use the @classmethod decorator and cls parameter.

Python

class Book:
    count = 0
    def __init__(self, title, author):
        self.title = title
        self.author = author
        # Your code here
    @classmethod
    def get_count(cls):
        # Your code here

Need a hint?

Remember to increase Book.count inside __init__ and use @classmethod for get_count.

3

Add a static method to validate book titles

Add a static method called is_valid_title that takes a title parameter and returns True if the title is a non-empty string, otherwise False. Use the @staticmethod decorator.

Python

class Book:
    count = 0
    def __init__(self, title, author):
        self.title = title
        self.author = author
        Book.count += 1
    @classmethod
    def get_count(cls):
        return cls.count
    @staticmethod
    def is_valid_title(title):
        # Your code here

Need a hint?

Use isinstance(title, str) and check if length is greater than zero.

4

Create Book objects, use methods, and print results

Create two Book objects called book1 and book2 with titles and authors. Print the number of books using Book.get_count(). Then print whether the title "Python 101" is valid using Book.is_valid_title("Python 101").

Python

class Book:
    count = 0
    def __init__(self, title, author):
        self.title = title
        self.author = author
        Book.count += 1
    @classmethod
    def get_count(cls):
        return cls.count
    @staticmethod
    def is_valid_title(title):
        return isinstance(title, str) and len(title) > 0

# Your code here

Need a hint?

Create two books, then print the count and check if "Python 101" is a valid title.