我应该如何增加 python 代码中的分数变量？

Question

from turtle import Turtle

SCORE=0

class Scoreboard(Turtle):


    def __init__(self):
        super().__init__()
        self.color("white")
        self.up()
        self.hideturtle()
        self.goto(-10,290)
        self.write(f"score : {SCORE} ",align="center",font=("Arial",16,"normal"))
    

    def score_change(self):
        SCORE+=1
        self.__init__()'''

I am new to this python.I want to increase the SCORE variable when i call the method from main.py but i am getting error like local variable 'SCORE' referenced before assignment.I know some posts are there with this error but i want to find the solution for this code.

Answer 1

Please add the global keyword before SCORE in the function as SCORE is a global variable . So when you do SCORE += 1 then SCORE is not found as in python you need to explicitly tell global to access variables not encapsulated in class else they are interpreted as static members of class as in your case.

Change you method as below

def score_change(self):
    global SCORE # add this line
    SCORE += 1
    self.__init__()

Corrected source:

from turtle import Turtle

SCORE = 0


class Scoreboard(Turtle):
    def __init__(self):
        super().__init__()
        self.color("white")
        self.up()
        self.hideturtle()
        self.goto(-10,290)
        self.write(f"score : {SCORE} ",align="center",font=("Arial",16,"normal"))

    def score_change(self):
        global SCORE
        SCORE += 1
        self.__init__()


if __name__ == '__main__':
    src = Scoreboard()
    src.score_change()
    src.score_change()
    src.score_change()
    print(SCORE)


# Output:
3

Also i would suggest if the SCORE is only used in the context if the Scoreboard Class then you should make it a static member as below and change the def score_change() method as it was previous. And access the SCORE how we access static members. like Scoreboard.SCORE

my Suggestion Source:

from turtle import Turtle


class Scoreboard(Turtle):
    SCORE = 0

    def __init__(self):
        super().__init__()
        self.color("white")
        self.up()
        self.hideturtle()
        self.goto(-10,290)
        self.write(f"score : {Scoreboard.SCORE} ",align="center",font=("Arial",16,"normal"))

    def score_change(self):
        Scoreboard.SCORE += 1
        self.__init__()


if __name__ == '__main__':
    src = Scoreboard()
    src.score_change()
    src.score_change()
    src.score_change()
    src.score_change()
    src.score_change()
    print(Scoreboard.SCORE)