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Python

Suraj Shah
Suraj Shah
1,055 Points
Posted by Suraj Shah
Suraj Shah
1,055 Points

BookCase uses the Book class without calling parent class?

In the BookCase class, we inherit from the Book class to get the title and author and append it to the book list. 

books.append(Book(title, author))

but when we create the BookCase class, we don't use:

class BookCase(Book)

how is it that the code still works?

full code here:

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_bookcase(cls, book_list):
      books = []
      for title, author in book_list:
        books.append(Book(title, author))
        return cls(books)

1 Answer

Chris Freeman
MOD
Chris Freeman
Treehouse Moderator 68,423 Points
Chris Freeman
Chris Freeman
Treehouse Moderator 68,423 Points

To clarify, the class BookCase does not inherit from the class Book as noted in the declaration line

class BookCase:

BookCase has one attribute books that is a list of Book objects. During BookCase.__init__, new Book objects are added to the attribute BookCase.books.

Post back if you need more help. Good luck!!!

Suraj Shah
Suraj Shah
1,055 Points
Suraj Shah
Suraj Shah
1,055 Points

Chris Freeman , thanks for your response.

I guess my confusion was in the BookCase class, we have a class method which has a line books.append(Book(title, author)), we are calling the Book class that we wrote earlier in the programme.

If I were writing the code from scratch, I would have written class BookCase(Book)

Just trying to understand why we did not do this here.

Chris Freeman
Chris Freeman
Treehouse Moderator 68,423 Points
Chris Freeman
Chris Freeman
Treehouse Moderator 68,423 Points

The difference is that we want Bookcase to be it's own class but include references to another class. This is a structural hierarchy of classes instead of an inherited hierarchy of class definition.