Welcome to the Treehouse Community

The Treehouse Community is a meeting place for developers, designers, and programmers of all backgrounds and skill levels to get support. Collaborate here on code errors or bugs that you need feedback on, or asking for an extra set of eyes on your latest project. Join thousands of Treehouse students and alumni in the community today. (Note: Only Treehouse students can comment or ask questions, but non-students are welcome to browse our conversations.)

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and a supportive community. Start your free trial today.

Python Object-Oriented Python Dice Roller RPG Roller

I don't understand how to do this

I know I'm not doing this right, but to be honest I don't know exactly how to do it. Any help would be much appreciated!

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, sides=20):
        super().__init__(sides)
hands.py
from dice import D20

class Hand(list):
    @property
    def total(self):
        return sum(self)

    @classmethod
    def roll(cls, number_of_dice):
        hand = Hand()
        for die in number_of_dice:
            hand.append(D20(die))
        return hand

Here's the question: In the hands.py file import the D20 class from dice.py. Create a classmethod named roll. Since it is a classmethod, it will take cls as an argument. It will also take the number of dice as an argument. Inside the roll classmethod create a new instance of the Hand class and assign it to a variable. Append a D20 to your Hand equal to the number of dice given as an argument to the roll classmethod. Then return the Hand of D20s. For example, if Hand.roll(2) is called, it would return a list with two D20s inside.

1 Answer

Chris Freeman
MOD
Chris Freeman
Treehouse Moderator 67,778 Points

Hey Amy Murphy, you’re very close:

  • need to use hand = cls() instead of Hand() since Hand is not yet fully defined
  • need to use for die range(number_of_dice): to repeat based on count.
  • need to append D20() as using D20(die) would append a n-sided die where n is the number_of_die

Not sure why D20 taking an argument passes the challenge. It should have been coded with no sides parameter and the call to die(20) fix with 20.

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

That worked perfectly, thanks for the help!