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Marco Koopman
5,290 PointsHow to global scope a var in a class
Hey!
I'm wondering how you can make a variable global ( so that I don't have to use 'self').
Normally it works to define it right under the class and above the constructor but in Python this gives me a scoping error.
class RaceCar:
laps = 0
def __init__(self, color, fuel_remaining, **kwargs):
self.color = color
self.fuel_remaining = fuel_remaining
for key, value in kwargs.items():
setattr(self, key, value)
def run_lap(length):
laps += 1
self.fuel_remaining = self.length * 0.125
2 Answers
Dave StSomeWhere
19,870 PointsI think your issue is that you are missing self in your run_lap() method def - not any issue with scoping.
The scoping seems fine (as you described) if the following code is what you meant:
class RaceCar:
test_var = "hello Race Car"
test2 = "Gonna assign to instance"
def __init__(self, color, fuel_remaining, **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):
self.fuel_remaining -= length * 0.125
self.laps += 1
test_var = "changed in runlap"
self.test2 = "Assigned to Instance***"
print("test_var in runlap ==> " + test_var)
print("self.test2 in runlap ==> " + self.test2)
a = RaceCar("Blue", 100)
a.run_lap(25)
print("fuel remaining ==> " + str(a.fuel_remaining))
print("test var ===> " + a.test_var)
print("test2 ===> " + a.test2)
Marco Koopman
5,290 PointsHey!
I've ajusted the code and it doesn't give any errors anymore. However the fuel_remaining variable isn't changing. I really don't understand how this scoping works.
class RaceCar:
laps = 0
def __init__(self, color, fuel_remaining, **kwargs):
self.color = color
self.fuel_remaining = fuel_remaining
for key, value in kwargs.items():
setattr(self, key, value)
def run_lap(self, length):
RaceCar.laps += 1
self.fuel_remaining = length * 0.125
print(self.fuel_remaining)
Marco Koopman
5,290 PointsMarco Koopman
5,290 PointsHey! Thanks for the reply. I already fixed the missing self parameter but I still get an error saying the variable 'laps' is referenced before assignment
Dave StSomeWhere
19,870 PointsDave StSomeWhere
19,870 PointsYes, I see what you are talking about - laps doesn't exist without any reference. It need to be either
self.lapsfor the instance orRaceCar.lapsfor the class. Justlapsdoesn't exist and attemptinglaps += 1results in an error within the method.