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Andrei Oprescu
9,547 PointsI don't know what I did wrong
So I have a challenge that asks me to do this:
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.
I have done everything that the challenge asked me but I still get an error saying 'Can't get the length of a 'Hand''
My code is at the bottom of the question.
Can someone help me figure it out?
Thanks!
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)
from dice import D20
class Hand(list):
def __init__(self, die_class=D20):
super().__init__()
def roll(self, size):
for _ in range(size):
self.append(die_class())
@property
def total(self):
return sum(self)
2 Answers
Chris Freeman
Treehouse Moderator 68,457 PointsYou are almost there. The following needs to be corrected:
- Since the access is from class
Handand not an instance ofHand, the method should be decorated with@classmethod. Also, as a classmethod, use cls instead of self in the parameter list to make it clearer. - As a classmethod there is no instance to operation on. To create one, use
hand = cls() - As a classmethod,
die_classwill not have been passed in or defined. Instead, usedD20directly. Also, remember to append tohandinstead ofself - Lastly, remember to
returnthe objecthand
Post back if you need more help. Good luck!!
Cristina Vasco
3,487 PointsI also have this error! It keeps saying
Bummer! Can't get the length of a `Hand`
My dice.py is identical to Andrei's. My hands.py is below, it works just fine in the workspace.
import dice
class Hand(list):
def __init__(self, count=0, diecls=None, *args, **kwargs):
if not diecls:
raise ValueError("You must provide a die class")
if not issubclass(diecls, dice.Die):
raise TypeError("You must provide a type of die as die class")
super().__init__()
for _ in range(count):
self.append(diecls())
self.sort()
@classmethod
def roll(cls, count):
return cls(count=count, diecls=dice.D20)
@property
def total(self):
return sum(self)
Chris Freeman
Treehouse Moderator 68,457 PointsComment out the line self.sort. The D20 & Die class does not defined the comparison magic methods needed for sort. Actual error:
Traceback (most recent call last):
File "<string>", line 3, in <module>
File "hand.py", line 18, in roll
return cls(count=count, diecls=dice.D20)
File "hand.py", line 14, in __init__
self.sort()
TypeError: unorderable types: D20() < D20()
Cristina Vasco
3,487 PointsGreat! thanks for this tip. My workspace version had the gt and lt magic methods implemented, so that's why it worked there and not in the challenge.
I guess this challenge was meant to work with minimal changes, I found a shorter solution after reading discussions on other questions for this challenge - you can get away with not even overriding Hand class's init!