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Python Python Testing Be Assertive Membership and Other Assertions

Posted by cathal britton
cathal britton
16,664 Points

self.hand1.results[0].value

Hi there I understand the line self.hand1.results[0] but don't understand the .value part at the end of it, isn't the 'value' attribute part of the class Die and not the class Roll? I'm a bit confused to what exactly going on with it. Could someone help me thanks.

1 Answer

Chris Freeman
MOD
Chris Freeman
Treehouse Moderator 68,457 Points
Chris Freeman
Chris Freeman
Treehouse Moderator 68,457 Points

Let's parse some code.

# a hand is the results of a dice.Roll()
self.hand3 = dice.Roll('3d6')

# the Roll __init__ function defines 'results' as:
for _ in range(num):
                self.results.append(Die(sides))

# So 'results' is an array where each item is one Die object

# In the Die object, 'value' is initialize to the random output of Die.roll() method
class Die:
    value = None

    def __init__(self, sides=6):
        try:
            assert sides >= 2
        except AssertionError:
            raise ValueError("Die needs at least 2 sides")
        else:
            self.sides = sides
        self.value = self.roll()  # define `value` based on roll() method

    def roll(self):
        return random.randint(1, self.sides)

So self.hand1.results[0].value is the value of the Die object in the first index of the results array.

Post back if you need more details.

cathal britton
cathal britton
16,664 Points

I understand it now, thanks for the help Chris. I really appreciate it.

Flore W
Flore W
4,744 Points
Flore W
Flore W
4,744 Points

Hi Chris Freeman

What's the value added of adding 'value' to 'self.hand1.results[0].value?

If I have in my console:

>>> from dice import Roll
>>> hand1 = Roll('2d6')
>>> hand1.results
[4,5]
>>> hand1.results[0]
4
>>> hand1.results[0].value
4

Can I just get away with self.hand1.results[0]? without the '.value'?