python - 名称错误 : name 'MainCorridor' is not defined

Question

我正在学习 LPTHW，并致力于制作自己的游戏。

class Engine(object):

    location_dict = {
        'main_corridor': MainCorridor(),
    }

    def goto(self, location):
        return Engine.location_dict.get(location).start()

    def test(self):
        print "Calling Engine() from MainCorridor()"    


class MainCorridor(object):

    def __init__(self):
        self.engine = Engine()

    def start(self):
        self.engine.test()



game = Engine()
game.goto('main_corridor')

有人可以建议我如何解决这个问题吗？非常感谢，谢谢

这是错误消息:

Traceback (most recent call last):
    File "ex45_game.py", line 1, in <module>
        class Engine(object):
    File "ex45_game.py", line 4, in Engine
        'main_corridor': MainCorridor()
NameError: name 'MainCorridor' is not defined

Answer 1

我最近做了 lpthw 教程。 Zed 所做的是创建第三个类来映射游戏中的级别，这样可以在定义其余类后实例化它们。这应该可以修复“未定义”错误。

但另一个问题是您最后要创建一个引擎对象:

game = Engine()

然后，当您初始化 MainCorridor 类时，您将创建一个单独的引擎对象:

class MainCorridor(object):

    def __init__(self):
        self.engine = Engine()

解决方案是仅在 MainCorridor 类中创建引擎类:

class Engine(object):

    def test(self):
        print "Calling Engine() from MainCorridor()"    


class MainCorridor(object):

    def __init__(self):
        self.engine = Engine()

    def start(self):
        self.engine.test()


class Map(object):

    location_dict = {
        'main_corridor': MainCorridor(),
    }

    def goto(self, location):
        map = self.get_location(location)
        return map.start()

    def get_location(self, location):
        return self.location_dict[location]


game = Map()
game.goto('main_corridor')

但是这样，您放入 location_dict 中的每个位置实例都将拥有自己唯一的 Engine 对象。

要为每个位置提供单个引擎对象，您可以将“self”从引擎传递到 map 类，并让 map 类通过将相同的引擎对象传递到列表中的每个位置来实例化 location_dict:

class Engine(object):

    def __init__(self):
        self.map = Map(self)

    def test(self):
        print "Calling Engine() from MainCorridor()"    


class MainCorridor(object):

    def __init__(self, engine):
        self.engine = engine

    def start(self):
        self.engine.test()


class Map(object):

    def __init__(self, engine):
        self.location_dict = {
            'main_corridor': MainCorridor(engine),
        }

    def goto(self, location):
        map = self.get_location(location)
        return map.start()

    def get_location(self, location):
        return self.location_dict[location]


game = Engine()
game.map.goto('main_corridor')