Question

我正在尝试理解我收到的错误消息（问题主题行）。我怀疑它可能与范围和嵌套逻辑有关。

以下是相关代码块：

class Smaug(Scene):

def enter(self):
    print "Smaug is a terrifying huge fire breathing dragon, but you must get the Arkenstone from him for Thorin"       
    print "In Smaug's cave, the Lonely Mountain, Smaug notices your presence and challenges you to a game"
    print "He says \"Guess a number between 1 and 3\""
    smaugNum = random.randint(1, 3)
    guesses = 0

    def guess():

        while guesses < 4:
            print "Guess a number between 1 and 3"
            numb = raw_input("> ")

            if numb == smaugNum:
                print "Well done! You win."
                Player.BilbosStuff.append('arkenstone')
                print "Now Bilbo has", Player.BilbosStuff
                return 'finished'

            else:
                print "You lose!"
                guesses += 1
                guess()

        print "Too many failed guesses, you lose!"
        return 'death'

这段代码使用引擎运行，引擎是一个类：

class GameEngine(object):

    def __init__(self):
        self.scenes = {'TheTrolls':TheTrolls(), 'MistyMountainsAndGollum':MistyMountainsAndGollum(), 'Smaug':Smaug(), 'death':death()}

    def run(self):

        next = 'TheTrolls'
        while True:
            if next == 'finished':
                print "Well done! You won!"
                exit(1)
            next = self.scenes.get(next).enter()


GameEngine().run()

“游戏”（这是我正在完成的教程）在将guess（）函数添加到Smaug（）之前确实有效。

但这是输出：

Traceback (most recent call last):   File "ex45.py", line 21, in
<module>
    GameEngine().run()   File "ex45.py", line 18, in run
    next = self.scenes.get(next).enter() AttributeError: 'NoneType' object has no attribute 'enter'

我的想法是，在while循环中return 'finished'可能不是父块的返回？还是我离开了？我是学习者。

Answer 1

您的问题是代码形式：

if next not in scenes:
    scenes.get(next) == None

因此错误：正如消息告诉您的那样，None没有enter属性！尝试

next = scenes.get(next)
if next is not None:
    next.enter()
else:
    print("No more scenes")
    break # leave the loop

Answer 2

您可以从错误中看到self.scenes.get(next)导致None。可能有很多原因，但我想这是death()调用返回无。

AttributeError：'NoneType'对象没有属性'enter'

2 个答案: