Project: Library Management System

Week 3 Milestone

You’ve made it through the most challenging part of Python: Object-Oriented Programming. Now, let’s combine your skills in classes, methods, and nested data to build a Library Management System.

Project Requirements

Your application should allow a user to:

1. Register a new book (with title, author, and ISBN).
2. Search for books by title.
3. Borrow/Return books (updating their status).
4. Log Transactions (record when a book was borrowed using datetime).

Step 1: Modeling the Book

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from datetime import datetime

class Book:
    def __init__(self, title, author, isbn):
        self.title = title
        self.author = author
        self.isbn = isbn
        self.is_available = True
        self.history = [] # List to store borrowing dates

    def borrow(self):
        if self.is_available:
            self.is_available = False
            self.history.append(f"Borrowed on: {datetime.now()}")
            return True
        return False

    def __str__(self):
        status = "Available" if self.is_available else "Borrowed"
        return f"{self.title} by {self.author} [{status}]"

Step 2: The Library Class

Use a dictionary to store books, using their ISBN as a unique key.

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class Library:
    def __init__(self):
        self.books = {} # ISBN -> Book Object

    def add_book(self, book):
        self.books[book.isbn] = book

    def list_books(self):
        for book in self.books.values():
            print(book)

Your Challenge

Complete the CLI interface in a main() function:

• Implement a loop that shows a menu (1. Add, 2. List, 3. Borrow, 4. Exit).
• Handle the logic for “Borrowing” a book by asking for its ISBN.
• Bonus: Add error handling to prevent the program from crashing if an ISBN isn’t found.

Interactive Practice

Visualize the relationship between the Library and its Books.