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Python Basic Object-Oriented Python Emulating Built-ins Emulating Built-ins

Jacques Dutoit
Jacques Dutoit
5,142 Points
Posted by Jacques Dutoit
Jacques Dutoit
5,142 Points

How do you use the __eq__ method correctly?

here is my code : class Book: def init(self, author, title): self.author = author self.title = title

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

here is the question to answer: Add a eq method for this book class. It should check if the author and title of the book are the same and return true if they are and false if they aren’t.

my current answer: 

def __eq__(self,other):
      return self.author == other.author and self.title == other.title.

Doesn't seem to work

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

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

    def __eq__ (self, other):
        return self.author == other.author and self.title == other.title
bookcase.py 
from book import Book


class BookCase:
    def __init__(self):
       self.books = []

    def add_books(self, book):
        self.books.append(book)

1 Answer

Travis Alstrand
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.a{fill-rule:evenodd;}techdegree seal-36
Travis Alstrand
Data Analysis Techdegree Graduate 49,443 Points
Travis Alstrand
.a{fill-rule:evenodd;}techdegree seal-36
Travis Alstrand
Data Analysis Techdegree Graduate 49,443 Points

Hiya Jacques Dutoit !

What you have in both of those code blocks for the __eq__ method have very slight issues that would need to be addressed but basically what you have is correct.

  1. In the top code block there is a stray period at the end of the conditional that would need to be removed

  2. In the larger code block, there cannot be a space between __eq__ and the parens (self, other)

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

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

    def __eq__(self, other):
        return self.author == other.author and self.title == other.title

Nice work! Just little syntax errors 👍