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Python Object-Oriented Python Dice Roller RPG Roller

Posted by Jake Williams
Jake Williams
2,900 Points

RPG Roller challenge part 2.

I found three different answers regarding this particular challenge and none of them seem to be working out for me. What am I doing wrong?

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)

    @classmethod
    def roll(cls, num_of_dice):
        Hand = cls()
        for _ in range(num_of_dice):
            Hand.append(num_of_dice())
        return (Hand())
Jake Williams
Jake Williams
2,900 Points

Can't get the length of a Hand

from dice import D20

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

    @classmethod
    def roll(cls, D20):
        self = cls()
        for _ in range(D20):
            self.append(D20())
        return (self)

[Mod: there needs to be a blank line above and below triple backticks ```. adding python will colorize]

1 Answer

Chris Freeman
MOD
Chris Freeman
Treehouse Moderator 68,423 Points
Chris Freeman
Chris Freeman
Treehouse Moderator 68,423 Points

Hey Jake Williams, Here some errors to fix:

  • :point_right: the item appended should be an D20() instance, not "num_of_dice"
  • :point_right: the object return should be the object created "Hand" not "Hand()"

Other areas to fix (not needed to pass, but good coding practice:

  • Do not use the class name Hand as a local method variable name. In class methods, self is a good name to use since you are creating an instance.

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

Jake Williams
Jake Williams
2,900 Points

I am still struggling with this. Tells me "Didn't get D20s in my Hand instance". Is this how you want me to do it? 

from dice import D20

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

    @classmethod
    def roll(cls, D20):
        self = cls()
        for _ in range(D20):
            self.append(D20)
        return (self)
Chris Freeman
Chris Freeman
Treehouse Moderator 68,423 Points
Chris Freeman
Chris Freeman
Treehouse Moderator 68,423 Points

You're almost there. An instance of D20() should be appended. Not the class reference D20. I've edited my answer above to clarify this.

You got this!!

Chris Freeman
Chris Freeman
Treehouse Moderator 68,423 Points
Chris Freeman
Chris Freeman
Treehouse Moderator 68,423 Points

Sorry, missed one more error. The parameter name can not be "D20". This creates a local variable local to the method named "D20" that prevents the method from accessing the imported D20.

  • :point_right: change the parameter D20 and the range argument to something else. You had num_of_dice before. That would be a good choice.
Jake Williams
Jake Williams
2,900 Points

Whoa Boy!!! Don't know why that was so tricky for me.