如何使用Pickle加载类实例（初学者支持到pickle jar中）

Question

I have been going through previous SO answers and have yet to find an answer. I am trying to save and load a class instance with pickle and I keep getting the error: type object 'Foo' has no attribute 'bar'. my code is below:

class Char:
    name = "undefined"

    def __init__(self, race, str, int, dex, con, spd, mp_bonus):
        self.race = race
        self.exp = 0
        self.lvl = 1
        self.str = str
        self.int = int
        self.dex = dex
        self.con = con
        self.spd = spd
        self.hp = (con + str) / 2
        self.current_hp = self.hp
        self.mp_bonus = mp_bonus
        self.mp = (int * mp_bonus)
        self.current_mp = self.mp

    def save(self):
        with open("save.pk1", "wb") as fp:
            pickle.dump(self.__dict__, fp, protocol=pickle.HIGHEST_PROTOCOL)

def load():
    with open('save.pk1', 'rb') as fp:
        Char.__init__ = pickle.load(fp) # no idea what to put here 
                                        # or if it should be in the Char class or not

def options(dude):
    cls()
    print("OPTIONS")
    print("_____________________")
    print("s. Save Game")
    print("l. Load Game")
    print("x. Quit Game")
    print("_____________________")
    select = input("please type in the corresponding letter or number: ")

    if select == "s":
        Char.save(player)
        cls()
        print("Save Complete")
        wait()
        main(dude)
    elif select == "l":
        cls()
        print("Load Complete")
        wait()
        main(dude)
    elif select == "x":
        exit_screen(dude)
    else:
        print("you chose the wrong key")
        wait()
        main(dude)

  def main(dude):
      #menu as written in options above
      select = input("please type in the corresponding letter or number: ")

      if select == "s":
           stats(dude)
      elif select == "i":
           inventory(dude)
      elif select == "1":
           rand_enemy()
      elif select == "o":
           options(dude)
      else:
           print("you chose the wrong key")
           wait()
           main(dude)

   def start_screen(char):
       #menu as written in options above

       select = input("Please type in the corresponding number: ")

       if select == "1":
           get_char(char)
       elif select == "2":
           load()
           main(char)
       elif select == "3":
           exit()
       else:
           print("you chose the wrong key")
           wait()
           start_screen(char)

start_screen(Char)

So my main issue is that when I try to load the game, it tells me: AttributeError: type object 'Char' has no attribute 'lvl'

While I cannot understand the pk1 file, It is being updated with each save, so I know that the save functionality is working properly.. I am just not sure how to take the information in the pk1 file and replace it with Char. init

I am thinking about just switching to JSON because I have it implemented in other parts of my code.. but I would like to make my life easier by using pickle in this case

Answer 1

Your approach of dumping self. dict looks a bit convoluted to me. The common way to dump an instance of your class Char would be as follows:

class Char:
    def save(self):
        with open("save.pk1", "wb") as fp:
            pickle.dump(self, fp, protocol=pickle.HIGHEST_PROTOCOL)

def load():
    """returns the saved instance of Char"""
    with open('save.pk1', 'rb') as fp:
        return pickle.load(fp)

For sake of clearness, I will add the usage of the above class and method.

$ python -i 53796917.py
>>> c=Char()
>>> c.lvl = 10
>>> c.save()
>>>
$ python -i 53796917.py
>>> c=load()
>>> c.lvl
10

Doesn't throws any AttributeError