Library

Background

Library is a popular place to get a book when you need one. You might use it to get school books, or just to borrow a book to read. But have you ever wondered how the registration app works? Or what happens when you borrow a book?

In a file called library.py, implement a program in Python where you would simulate that app, you should do this by rewriting the distribution code below. The program should have two classes: Book and Library.

Understanding

Each book has a title, author and a genre.

A book can be borrowed, and returned. Also you can display info about each book that would be structured as title by author.

In a Library you can add a book to its collection. Find a book by its title and author. Find all books that are available, borrowed or a specific genre.

Before You Begin

Execute cd by itself in your terminal window. You should find that your terminal window’s prompt resembles the below:

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$ 

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mkdir library 

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cd library 

code library.py

Specification

Book Class

• __init__ should initialize a book given title, author, genre, is_available where title, author, genre are passing in when creating an instance, and is_available represents if the book is available or not.
• borrow method should change is_available to false.
• return_book method should change is_available to true.
• display_info method should return the string of the book as title by author

Library Class - __init__ should have an attribute to store all books called books. - add_book method should append the book given to books. - find_book method should find the book given title and author and return it, else should return None - list_available_books method should list all available books, if there are none it should return an empty list. - list_borrowed_books method should list all borrowed books, if there are none it should return an empty list. - list_genre_books method should list all books with the given genre, if there are none it should return an empty list.

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books = []

def Book(title, author, genre):
    return {"title": title, "author": author, "genre": genre, "is_available": True}

def add_book(book):
    books.append(book)

def find_book(title, author):
    for b in books:
        if b["title"].lower() == title.lower() and b["author"].lower() == author.lower():
            return b
    return None

def list_available_books():
    available = []
    for b in books:
        if b["is_available"]:
            available.append(b)
    return available

def list_borrowed_books():
    available = []
    for b in books:
        if not b["is_available"]:
            available.append(b)
    return available

def list_genre_books(genre):
    temp = []
    for b in books:
        if b["genre"].lower() == genre.lower():
            temp.append(b)
    return temp

def borrow(book):
    for b in books:
        if b["title"].lower() == book["title"].lower() and b["author"].lower() == book["author"].lower() and b["is_available"]:
            b["is_available"] = False

def return_book(book):
    for b in books:
        if b["title"].lower() == book["title"].lower() and not b["is_available"]:
            b["is_available"] = True 

def display_info(book):
    return f"{book["title"]} by {book["author"]}"

Rewrite the code into a Class version of it.

Challenge

If up for a challenge, optionally implement a program that asks for user input to interact with your library. The program should support borrowing, returning, and searching for books using all of the methods described.

Remember to add at the if name main clause bottom of the file!

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if __name__ == "__main__":
    main()

How To Test

Here’s how to test your code manually:

Open your library.py file, create two Book instances (you can use this books as input: "The night, The fool and The Dead by Steve Cole, Scifi", "The Name of the Wind by Patrick Rothfuss, Fantasy"). Create a library instance.

• Use the add_book method to add at least one book to the library. Then print all of the books. You should see the books you added.

• Use the find book method to find a book you haven't added. It should return None. Then use it to find the book that is already there, and it should return the book's instance.

Use the borrow method on a book.

• Use the list_borrowed_books method, where you should see the book you have borrowed.

Use the return_book method on a book.

• Use the list_available_books method to list all of the books you have added. You should see the books you have added.

• Use the display_book method on a book, which should return title by author string.

• Use the list_genre_books method with a genre that is not in any books, it should return an empty list. Then use the method again but with a genre that is in some books, it should return all of the books with that genre.

If you run into an error saying your file cannot be opened, retrace your steps to be sure that you are inside your library folder and have saved your library.py file there.

You can execute the below to check your code using check50, a program that CS50 will use to test your code:

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check50 alum-challenges/problems/main/python/week-8/library/tests

• Green smiles mean your program has passed a test!
• Red frowns will indicate your program output something unexpected.
• Orange neutral faces mean you must fix the failed check before those checks can run.

Visit the URL that check50 outputs to see the input check50 handed to your program, what output it expected, and what output your program actually gave.

How to Submit

Coming soon