class Brick: def __init__(self, canvas, ltx, lty, rbx, rby, color): self.lx = ltx self.ly = lty self.rx = rbx self.ry = rby self.cvs = canvas self.color = color self.id = canvas.create_rectangle((ltx, lty, rbx, rby), fill=color) def exist(self, brick): if ball.isHit(brick) == 'Upper' or ball.isHit(brick) == 'Lower': self.cvs.delete(brick.id) bricks.remove(brick) ball.change_velocity_y() elif ball.isHit(brick) == 'Left' or ball.isHit(brick) == 'Right': self.cvs.delete(brick.id) bricks.remove(brick) ball.change_velocity_x() ball = Ball(canvas, 3, 5, 'red') paddle = Paddle(canvas, 10) bricks = [] n = 0 x = 50 y = 50 j = 10 while n < j: bricks.append(Brick(canvas, x, y, x+30, y+15, 'blue')) x = x + 20 y = y + 10 n = n + 1 while True: ball.fly() paddle.run() if ball.isHit(paddle) == 'Upper': ball.change_velocity_y() n = 0 while n < j: bricks[n].exist(bricks[n]) n = n + 1有什么错误

这段代码存在一个错误，即在Brick类的exist方法中，应该使用self来引用当前对象的属性和方法，而不是使用参数brick。正确的代码应该是：

class Brick:
    def __init__(self, canvas, ltx, lty, rbx, rby, color):
        self.lx = ltx
        self.ly = lty
        self.rx = rbx
        self.ry = rby
        self.cvs = canvas
        self.color = color
        self.id = canvas.create_rectangle((ltx, lty, rbx, rby), fill=color)
        
    def exist(self):
        if ball.isHit(self) == 'Upper' or ball.isHit(self) == 'Lower':
            self.cvs.delete(self.id)
            bricks.remove(self)
            ball.change_velocity_y()
        elif ball.isHit(self) == 'Left' or ball.isHit(self) == 'Right':
            self.cvs.delete(self.id)
            bricks.remove(self)
            ball.change_velocity_x()

ball = Ball(canvas, 3, 5, 'red')
paddle = Paddle(canvas, 10)
bricks = []
n = 0
x = 50
y = 50
j = 10
while n < j:
    bricks.append(Brick(canvas, x, y, x+30, y+15, 'blue'))
    x = x + 20
    y = y + 10
    n = n + 1

while True:
    ball.fly()
    paddle.run()
    if ball.isHit(paddle) == 'Upper':
        ball.change_velocity_y()
    n = 0
    while n < j:
        bricks[n].exist()
        n = n + 1

这样就可以正确地删除砖块并修改小球的速度了。