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Python Object-Oriented Python Advanced Objects Constructicons

Posted by Nicholas Abate
Nicholas Abate
1,643 Points

Book and Bookcase Relationship

How is it that in creating an instance using the classmethod create_bc that the title and author are passed to the Book class?

And we are appending a title and author to the books list. Would books = [title1, author1, title2, author2] in this case?

class Book:
    def __init__(self, title, author):
        self.title = title
        self.author = author

    def __str__(self):
        return '{} by {}'.format(self.title, self.author)

class Bookcase:
    def __init__(self, books = None):
        self.books = books

    @classmethod
    def create_bc(cls, book_list):
        books = []
        for title, author in book_list:
            books.append(Book(title, author))
        return cls(books)

book1 = Bookcase.create_bc([("title1", 'author1'), ('title2', 'author2')]) print(book1.books[0])

1 Answer

Steven Parker
Steven Parker
229,732 Points
Steven Parker
Steven Parker
229,732 Points

The "create_bc" method doesn't just add strings to a list, it adds Book objects to a list that is an attribute of a "Bookcase" instance. So:

book1 = [title1, author1, title2, author2]          # this is NOT what the example does
book1 = Bookcase([Book("title1", "author1"), Book("title2", "author2")])  # but this is