如何从python中的另一个导入模块引用一个模块中的变量？

Question

Menu:

import myGame as gameMod
def startGame(screen, level, musicVolume, effectsVolume, numControllers):
    game = gameMod.Game()
    game.main(screen, level, musicVolume, effectsVolume, numControllers)

myGame:

class Game(object):
    def main(self, screen, level, musicVolume, effectsVolume, numControllers):
    self.timer = 0

class EnemyBullet(pygame.sprite.Sprite):
    def __init__(self, location, kind, numShots, ID, *groups):
         self.dx = math.sin(game.timer) * 100

but this throws an error

NameError: global name 'game' is not defined

I'd like for the game.timer to be able to refer to the Game() instance created in Menu even though both EnemyBullet and Game classes are held within the myGame module. When the myGame module is run and these lines exist it works out without any errors. I assume this is because the Game() instance is global and can be found unlike the situation when it's imported.

if __name__ == "__main__":
    game = Game()
    game.main(screen, 1, 50, 0, 0)

Answer 1

I am not sure what is going on here. Didn't you import game as gameMod ? So, shouldn't it be gameMod.timer.

Now if you are calling timer from within the game module, then why can't you reference it directly as timer. I am assuming that timer is a variable in game and thus exists in its namespace.