python - 保存和加载类实例

Question

我有一个创建新角色对象的类。

class Character():
    def __init__(self):
    self.name = None
    self.hp = None
    self.mp = None


class Race(Character):
    def __init__(self):
    super().__init__()
    self.race = None

它位于一个名为 char 的模块中。所以我有了创建新游戏的代码。

    elif command == "new game":
        name_game = input('Name your game: ')

        cur_save=open('saves/' + name_game + '.p', 'wb')
        player = char.Character()
        player_name = input('Name your character: ')
        player.name = player_name
        player_race = input('What is your race? ')
        player.race = player_race
        pickle.dump(player, cur_save, -1)
        cur_save.close()

现在我想开始游戏并加载输入的玩家姓名和种族。但以下只是将玩家设置为未定义。

    cur_save=open('saves/' + name_game + '.p', 'rb')
    player = pickle.load(cur_save)

我希望它将player.name设置为保存的值，并与player.race相同。 还有其他我应该使用的东西，比如数据库之类的东西(MySQL)

Answer 1

所以我快速测试了一下，没有问题:

import pickle
class Character():
    def __init__(self):
        self.name = None
        self.hp = None
        self.mp = None


class Race(Character):
    def __init__(self):
        super().__init__()
        self.race = None

name_game = input('Name your game: ')

cur_save=open('saves/' + name_game + '.p', 'wb')
player = Character()
player_name = input('Name your character: ')
player.name = player_name
player_race = input('What is your race? ')
player.race = player_race
pickle.dump(player, cur_save, -1)
cur_save.close()

cur_save=open('saves/' + name_game + '.p', 'rb')
player = pickle.load(cur_save)
print(player.name)

我得到的是:

%run temp.py
Name your game: test
Name your character: Brian
What is your race? human
Brian

有时，如果你的类的定义发生了变化，或者即使你重新定义了类(也许通过再次运行一些代码)，我会发现 pickle 会失败。例如，假设我运行上面的第一段代码，然后运行

class Character():
    def __init__(self):
        self.name = None
        self.hp = None
        self.mp = None

再次，本质上重新定义了角色。然后你会得到不直观的行为:

In [17]: player.__class__
Out[17]: __main__.Character
In [18]: player.__class__ == Character
Out[18]: False

In [20]: player2 = Character()
In [21]: player2.__class__
Out[21]: __main__.Character
In [22]: player2.__class__ == Character
Out[22]: True

所以您可能想确保不会发生类似的事情。通常这并不重要，但如果变量名称发生变化或其他什么，它可能会让你失望。