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Python Object-Oriented Python Dice Roller RPG Roller

Isaac Stong
Isaac Stong
4,083 Points
Posted by Isaac Stong
Isaac Stong
4,083 Points

RPG Roller 2 of 2

I'm having an error Can't get the length of hand I've looked at other posts here and it seems like very similar code is working for others any help is appreciated thanks

dice.py 
import random


class Die:
    def __init__(self, sides=2):
        if sides < 2:
            raise ValueError("Can't have fewer than two sides")
        self.sides = sides
        self.value = random.randint(1, sides)

    def __int__(self):
        return self.value

    def __add__(self, other):
        return int(self) + other

    def __radd__(self, other):
        return self + other

class D20(Die):
    def __init__(self):
        super().__init__(20)
hands.py 
from dice import D20

class Hand(list):

    @classmethod
    def roll(cls, number):
        hand = cls
        for rolls in range(number):
            hand.append(D20())
        return hand

    @property
    def total(self):
        return sum(self)

3 Answers

Steven Parker
Steven Parker
231,236 Points
Steven Parker
Steven Parker
231,236 Points

You're very close! But when you create a new instance, place parentheses like you would when calling a function:

        hand = cls()
Isaac Stong
Isaac Stong
4,083 Points
Isaac Stong
Isaac Stong
4,083 Points

Thanks for the quick response Steven! I did as you said and added in the parentheses to pass cls as an instance, unfortunately, this did not get rid of the length problem the same error seems to pop up any ideas on this? Also I should add it complains about not being able to get the length of Hand with a capital H I don't know if that helps any.

Steven Parker
Steven Parker
231,236 Points
Steven Parker
Steven Parker
231,236 Points

If I paste your code directly into the challenge and make just that one change, it passes.

Perhaps restart your browser before you try again?

Isaac Stong
Isaac Stong
4,083 Points
Isaac Stong
Isaac Stong
4,083 Points

I restarted the browser a few hours later and all is working thank you for the help!

Than Win Hline
Than Win Hline
1,679 Points
Than Win Hline
Than Win Hline
1,679 Points

I don't understand this solution. Why we are using hand=cls() and what is the purpose of using classmethod here? I'm stuck with this solution

Steven Parker
Steven Parker
231,236 Points
Steven Parker
Steven Parker
231,236 Points

Note the example invocation shown in the instructions is "Hand.roll(2)", so it's obvious that the class itself (and not an instance) is being used to access the method. That lets you know that it should be implemented as a class method.

The instructions also say "I want to get back an instance of Hand ...", and calling "cls()" is the best-practice way to create a new instance inside a class method.

Than Win Hline
Than Win Hline
1,679 Points
Than Win Hline
Than Win Hline
1,679 Points

Thank you for the reply. Now I understood