如何编写一个class方法来模拟Python中的对象被另一个对象淘汰？

Question

我是第一次使用python class，所以如果代码对你们来说太笨拙，请原谅我。我想使用 python class 创建一个包含《权力的游戏》角色的 class，我在其中编写了一个 "kill" 函数来使一个角色杀死另一个角色，从而将 1 人添加到他的击杀记录（整数），被击杀的角色将从内存中删除，无法再访问。这是我的代码：

import gc
class Character():
  population = 0

  def __init__(self, name, house, castle):
      self.name = name
      self.house = house
      self.castle = castle
      self.kill=0
      print('{0} comes to the world of ice and fire!!!'.format(self.name))
      Character.population += 1

  def __str__(self):
      return 'I am {0} of house {1}, I live in {2}.'.format(self.name,
      self.house, self.castle)

  def __del__(self):  
      print ('{0} of house {1} has been slain.'.format(self.name, self.house))
      Character.population -= 1


  # My kill function:

  def kill(slayer, slain):
     print('{0} of house {1} has slain {2} of house {3}!'.format(slayer.name, slayer.house, slain.name, slain.house))
     slayer.kill +=1

     while len(gc.get_referrers(slain))!=0:
         del slain

c1=Character('Jofferry','Baratheon',"King's landing")
c2=Character('Eddard','stark','Winterfell' )

print('c1 has',len(gc.get_referrers(c1)),'reference(s)')
print('c2 has',len(gc.get_referrers(c2)),'reference(s)')

Character.kill(c1,c2)

一开始我是直接写的德尔斯兰在我的 kill 函数结束时，当我运行代码时，它给了我这个：

Jofferry comes to the world of ice and fire!!!
Eddard comes to the world of ice and fire!!!
c1 has 1 reference(s)
c2 has 1 reference(s)
Jofferry of house Baratheon has slain Eddard of house stark!
c1 has 1 reference(s)
c2 has 1 reference(s)

这意味着 del 函数根本不起作用。所以我尝试了 gc.get_referrers 函数并写道：

while len(gc.get_referrers(slain))!=0:
     del slain

但它给了我：

Jofferry comes to the world of ice and fire!!!
Eddard comes to the world of ice and fire!!!
c1 has 1 reference(s)
c2 has 1 reference(s)
Jofferry of house Baratheon has slain Eddard of house stark!
Traceback (most recent call last):
File "/home/xiasu/Meca3/Python/Whosebug.py", line 37, in Character.kill(c1,c2)
File "/home/xiasu/Meca3/Python/Whosebug.py", line 27, in kill while len(gc.get_referrers(slain))!=0:

   UnboundLocalError: local variable 'slain' referenced before assignment

我不明白这是什么意思。请帮助我，在此先感谢！（顺便说一句：在 python 中是否可以定义一个实例变量（例如：在我的例子中是配偶），它也是同一个 class （字符）中的对象？如果是，我该如何初始化它在'init'?)

Answer 1

你不能做你想做的事。你不能 "delete an object from memory"。 del 删除对象的引用（例如，名为 slain 的变量）。如果其他对象仍然持有对 "slain" 字符的引用，那是他们的事。你不能破坏他们的引用。

对于您的示例，尚不清楚为什么您仍然需要这样做。您可以在对象上设置一个标志，例如 slain.dead = True 以将角色标记为已死亡。

Answer 2

唯一明智的做法是将其全部包装在 class 中。

class GameOfThrones(object):

    def __init__(self, kingdom):
        self.kingdom = kingdom
        self.population = {}

    def create_character(self, *args, **kwargs):
        c = Character(*args, **kwargs)
        self.population[c.name] = c

    def kill_character(self, killer, victim):
        self.population[killer].kill(self.population[victim])
        del self.population[victim]

class Character(object):

    def __init__(self, name, house, castle):
        self.name = name
        self.house = house
        self.castle = castle
        self.victims = []
        self.alive = True

    @property
    def kills(self):
        return len(self.victims)

    def kill(self, other):
        other.dies()
        self.victims.append(other)
        print("{} killed {}".format(self.name, other.name))

    def dies(self):
        self.alive = False

game = GameOfThrones()

game.create_character("Joffrey", "Baratheon", "King's Landing")
game.create_character("Eddard", "Stark", "Winterfell")

game.kill_character("Eddard", "Joffrey")

也就是说，这只是勉强 "sane." 确实没有什么理由这样做。

如何编写一个class方法来模拟Python中的对象被另一个对象淘汰？

How to write a class method to simulate object being eliminated by another in Python?

python

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