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Python Object-Oriented Python Dice Roller RPG Roller

[SOLVED] Can't get the length of 'Hand'

Stuck on this challenge task 2/2, what exactly do they want here? What am I doing wrong?

EDIT: Solved the problem, I did not read the question correctly, the question states that it will call Hand.roll(). This means that the roll method shouldn't have a self as an argument.

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__(sides=20)
hands.py
from dice import D20


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

    def roll(self, num):
        some_hand = Hand()

        for _ in range(0, num):
            some_dice = D20()
            some_hand.append(some_dice)

        return some_hand

1 Answer

Steven Parker
Steven Parker
230,230 Points

This is a situation where @classmethod might be useful. Instead of a "self" argument you would get a "cls" argument that you could use for instantiating the hand.

But however you did it, congratulations on resolving your issue. :+1:

How would that look like? I thought something like:

class Hand(list):

    def __init__(self, size=0, die_class=None, *args, **kwargs):
        super().__init__()

        if not die_class:
            raise ValueError("No die_class.")

        for _ in range(0, size):
            self.append(die_class())

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

    @classmethod
    def roll(cls, num):
        return cls(size=num, die_class=D20)

But this keeps raising a ValueError, unless I change it to this:

def __init__(self, size=0, die_class=D20, *args, **kwargs):

Strange no?

Steven Parker
Steven Parker
230,230 Points

That makes sense because without a default value for die_class it would be a required argument and before the override of __init__ was added, it was not required. So when the challenge tests creating a plain instance of Hand, it would fail.