Python Object-Oriented Python Dice Roller RPG Roller

Class method that appends a die as many times as the number in args

Task: In the hands.py file import the D20 class from dice.py. Create a classmethod named roll. It should take take the number of dice as an argument. Inside the roll classmethod create an empty list. Append a D20 to your list equal to the number of dice given as an argument to the roll classmethod. Then return the list of D20s. For example, if Hand.roll(2) is called, it would return a list with two D20s inside.

Question: My method takes a number of dice, creates a new list and iterates through the range of the number given as argument. For each iteration, the list appends a D20. What am I not seeing?

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)

    @class method
    def roll(number_of_dice):
        dicelist = []
        for i in range(1,number_of_dice):
            dicelist.append(D20)
        return dicelist

1 Answer

Steven Parker
Steven Parker
201,997 Points

There are a few issues:

  • "@classmethod" should be one word
  • the first parameter in a class method should be "cls"
  • the internal list should be an instance of "Hand" (created using "cls")
  • the range should start at 0 (or you can just omit the first argument)
  • to create a new instance, "D20" must be followed by parentheses
    @classmethod
    def roll(cls, number_of_dice):
        dicelist = cls()
        for i in range(number_of_dice):
            dicelist.append(D20())
        return dicelist

Oh...My code was actually so sloppy now that I read your comment. Thank you very much

Johnny Austen
seal-mask
.a{fill-rule:evenodd;}techdegree
Johnny Austen
Python Development Techdegree Student 4,874 Points

Hi Steven, would you be able to explain how you got to this point at all?

I'm wondering why the new list needs to be an instance of its' parent, hand?

And also what is actually being taken from D20, just the number of sides? I'm a bit confused about D20's involvement I think.

Steven Parker
Steven Parker
201,997 Points

The instructions should explicitly ask for you to return an instance of Hand, and they used to. They were apparently changed recently for some reason, and I've already submitted a bug report. If you want to submit one also it wouldn't hurt.

The entire D20 object instance (or reference to it) is stored in the Hand. Nothing is taken from it.