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Python Object-Oriented Python Dice Roller RPG Roller

Posted by Ömer Faruk Özsakarya
Ömer Faruk Özsakarya
2,071 Points

I could not find out how to solve this task.

I tried to add some methods and I do not understand how I can solve this problem.

Challenge is: https://teamtreehouse.com/library/objectoriented-python-2/dice-roller/rpg-roller

                                                      Challenge Task 2 of 2

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 
from dice import D20

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

    def __init__(self):
        self.dies = []

    @classmethod
    def roll(size):
      print(size)
      hand_with_two_d20 = Hand()

      for _ in range(size):
        hand_with_two_d20.dies.append(D20())

      return hand_with_two_d20

    def __len__(self):
        return len(self.dies)

print(Hand.roll(2))

When I run the code, I am getting the error message below:

Traceback (most recent call last): File "hands.py", line 24, in <module> print(Hand.roll(2)) TypeError: roll() takes 1 positional argument but 2 were given 

2 Answers

Steven Parker
Steven Parker
231,248 Points
Steven Parker
Steven Parker
231,248 Points

The system provides the first parameter to a method, and for a class method it will be a reference to the class itself. By convention the parameter name given for this is "cls". You can call it from inside the method to create a new instance.

"Hand" should not have a "dies" attribute. It is a type of list, so you can append items directly to an instance.

And this method doesn't need to "print" anything.

Ömer Faruk Özsakarya
Ömer Faruk Özsakarya
2,071 Points
Ömer Faruk Özsakarya
Ömer Faruk Özsakarya
2,071 Points

Thank you!