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Python Object-Oriented Python Instant Objects Master Class

Posted by Chirstopher Herdeg
Chirstopher Herdeg
7,451 Points

racer task 3

how to solve the task 3 problem in python OOP with the RaceCar and Laps question

racecar.py 
class RaceCar:
    def __init__(self, color, fuel_remaining,laps, **kwargs):
        self.laps = 0
        self.color = color
        self.fuel_remaining = fuel_remaining

        for key, value in kwargs.items():
            setattr(self, key, value)
    def run_lap(self, length):
        laps += 1
        return fuel_remaining -= self.length * 0.125

1 Answer

Asher Orr
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.a{fill-rule:evenodd;}techdegree seal-36
Asher Orr
Python Development Techdegree Graduate 9,410 Points
Asher Orr
.a{fill-rule:evenodd;}techdegree seal-36
Asher Orr
Python Development Techdegree Graduate 9,410 Points

Hi Chirstopher! Do you mean Task 2? I ask since the code you provided does not pass Task 2 in the challenge.

Regardless, I'll go over both questions with you.

Task 2: Add a laps attribute to the RaceCar class and set it to 0. Add a method named run_lap. It'll take a length argument. It should reduce the fuel_remaining attribute by the length argument multiplied by 0.125 (length * 0.125). Also, increment the laps attribute by 1 each time the run_lap method is called.

In your code, you are missing the laps attribute for the RaceCar class. Check out the example below- the Dog class has a class attribute called species. The value is "Canis familiaris".

class Dog:
    species = "Canis familiaris"

    def __init__(self, name, age):
        self.name = name
        self.age = age

Also, there is an issue with your run_lap method:

    def run_lap(self, length):
        laps += 1
        return fuel_remaining -= self.length * 0.125

Remember that this method will be run on an instance of the RaceCar class. "laps" is a class attribute, so any instance of the RaceCar class will automatically have a laps value of 0. The init method defines the attributes when you make an instance. Like this:

my_instance = RaceCar("Red", 20)

In my_instance, the color is set to red. The fuel_remaining is set to 20 units. "laps" is a class attribute, so we don't need to define it upon making an instance. We know it is automatically set to 0.

To make your run_lap method work properly, you need to tell Python that the fuel_remaining and laps attribute on your instance are going to be changed whenever the run_lap method is called. They need a self. prefix attached to them.

Length is just an argument in your run_lap method, and not an attribute of the instance or class. It therefore does not need the self. prefix.

For task 3, all you need to do is set the laps attribute to 0 inside the init method.

I hope this helps. Let me know if you have any questions!