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Python Object-Oriented Python Dice Roller Compare and Contrast

Adam Teale
Adam Teale
10,989 Points
Posted by Adam Teale
Adam Teale
10,989 Points

Can't compare `Song`s to `int`s

Hey guys,

As far as I can tell this should be working ok - when I test it locally it passes the comparisons. What am I missing?

Thanks!

Adam

songs.py 
class Song:
    def __init__(self, artist, title, length):
        self.artist = artist
        self.title = title
        self.length = length

    def __eq__(self, other):
        return int(self.length) == int(other.length)

    def __gt__(self, other):
        return int(self.length) > int(other.length)

    def __lt__(self, other):
        return int(self.length) < int(other.length)

    def __le__(self, other):
        return int(self.length) < int(other.length) or int(self.length) == int(other.length)

    def __ge__(self, other):
        return int(self.length) > int(other.length) or int(self.length) == int(other.length)

    def __int__(self):
        return int(self.length)

    def __len__(self):
        return int(self.length)
Igor Ević
Igor Ević
5,827 Points

You can compare instance of Song class only with objects that have attribute length, because you use other.length in methods for comparisons.

Adam Teale
Adam Teale
10,989 Points
Adam Teale
Adam Teale
10,989 Points

Thank you Igorevi!

kgoldthorpe
kgoldthorpe
7,802 Points

I have found this challenge to be very fickle. This worked for me, and it only worked for me when I copied it from someone else's answer in this forum. I typed this in verbatim and it didn't work, but when I copied and pasted the code, it worked. 

    def __int__(self):
        return self.length

    def __eq__(self, other):
        return int(self) == other

    def __lt__(self, other):
        return int(self) < other

    def __gt__(self, other):
        return int(self) > other

    def __le__(self, other):
        return int(self) < other or int(self) == other

    def __ge__(self, other):
        return int(self) > other or int(self) == other

1 Answer

Neil Brown
Neil Brown
22,514 Points
Neil Brown
Neil Brown
22,514 Points

For anyone else who has this problem.

It appears that what Kenneth is testing our code for is twofold: whether he can compare two songs together using the operators, and whether he can compare a song with an int using the operators. The code posted above will compare two songs with no error. But, if an integer is passed into the method, this code is calling other.length, which is fine for a song object, but an integer does not have that attribute.

Each method needs to check if the parameter it is receiving is an integer. If it is, compare it to the parameter directly i.e int(self.length) > other. If it is a song object then compare with the object's length. int(self.length) > other.length