rpg roller part 2 'can't get length of hand'

Question

I'm really stuck. I see they want a class method and return an instance of hand. ok...but it says it can.t get the length of hand?...why wouldn't it? It should have the parent class len method right? I mean the init ought to make Hand instances basically lists right? What am i missing here?

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__(20)

hands.py

from dice import D20 

class Hand(list):

    def __init__(self):
        super.__init__()



    @classmethod
    def roll(cls,many):
        x = Hand()
        for _ in range(1, many):
            x.append(D20())
        return x



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

Answer 1 · 2017-12-08T04:57:12Z

December 8, 2017 4:57am

Hey Ryan Cross

You're quite close!

First, your __init__ function is unnecessary. You're not overriding anything there anyway. Python will call __init__ automatically when you instantiate Hand. You only write your own if you're modifying the base class.

Second, instead of calling Hand() to create a list, just initialize an empty list, like dice = []. The whole point of a class method is that you call it on a class, not an instance of a class, but you're creating an instance of a class to run a class method.

Third, if you call Hand.roll(2) it should create two dice, but the way you've used range, it's only going to create 1. That's because the second parameter in range() is an exclusive stop. If you call range(1, 2), you're going up to but not including 2, so the loop is only going to run 1 time. If you just pass the number to range, like range(2) it will run two times (0, 1).

Lastly, when you make a class method, it needs to return cls(), which is like converting the result to the class. In this case you pass in Hand as cls, do some stuff, and return cls(dice) which is like calling Hand(dice).

I just posted a detailed answer here: https://teamtreehouse.com/community/unable-to-create-a-roll-method-in-hand In general, I find it useful to first do a search to see if someone already answered my question. Most likely, many people had the same problem and it has been answered already. There are so many duplicate questions in the forum because people don't do this.

Also, I write and test the code in workspace because the error messages from the code challenge page are confusing and not helpful. Testing the code in workspace is much more helpful.

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Ryan Cross

Ryan Cross

rpg roller part 2 'can't get length of hand'

Ryan Cross

Ryan Cross

1 Answer

ursaminor

ursaminor

Ryan Cross

Ryan Cross