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Python Object-Oriented Python Dice Roller RPG Roller

Posted by rtkacddqbo
rtkacddqbo
9,662 Points

Not sure how to solve this! Creating Roll method inside Hand class

I've looked at other questions on this but still haven't managed to understand this challenge nor get the right code. This has been the first challenge to really stop me in my tracks - I understand what he's asking but I don't get the logic of how to implement it: "Now update Hand in hands.py. I'm going to use code similar to Hand.roll(2) and I want to get back an instance of Hand with two D20s rolled in it. I should then be able to call .total on the instance to get the total of the two dice. I'll leave the implementation of all of that up to you. I don't care how you do it, I only care that it works."

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 
class Hand(list):
    def __init__(self, sides, die_class=None, *args, **kwargs):
        if not die_class:
            raise ValueError("Need a die class")

        for _ in sides:
            self.append(die_class)

    @classmethod
    def roll(cls, size):
        hand = Hand(size, D20)
        return hand

    @property
    def total(self):
        return sum(self)
Alex Moats
Alex Moats
4,535 Points

I'm currently stuck about a half step ahead on this challenge but what it looks like is you want to specify your class inputs and return cls to Hand

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

You may also want to specify a default value for sides in your hands.py init method

def __init__(self, sides=0, die_class=None, *args, **kwargs):

1 Answer

Chris Freeman
MOD
Chris Freeman
Treehouse Moderator 68,426 Points
Chris Freeman
Chris Freeman
Treehouse Moderator 68,426 Points

You have the overall approach correct. The follow corrections are needed

  • add missing import in hands.py: from dice import D20
  • In __init__, call super().__init__() to fully initialize the list
  • Use range(sides) when looping to append die. _ in sides returns "'int' object is not iterable"
  • Use parens when calling die_class() to generate instances, otherwise it's just the class type, not an instance
  • In roll use cls passed in for class call: cls(size) vs Hand(size), and use die_class key_word argument

Post back if you have more questions. Good Luck!!

rtkacddqbo
rtkacddqbo
9,662 Points

Thanks for the help! I adjusted the code with your comments and it worked.