搁置：无法pickle<class'method'>：属性查找内置项。method失败

Question

我在用shelve存储一些数据。

Traceback (most recent call last):
    File "rogue.py", line 312, in <module>
    curses.wrapper(game)
File "/usr/lib/python3.3/curses/__init__.py", line 94, in wrapper
    return func(stdscr, *args, **kwds)
File "rogue.py", line 289, in game
    save_game(y,x)
File "rogue.py", line 119, in save_game
    file['player'] = player
File "/usr/lib/python3.3/shelve.py", line 124, in __setitem__
    p.dump(value)

_pickle.PicklingError: Can't pickle <class 'method'>: attribute lookup builtins.method failed

我环顾四周，发现一些关于未绑定方法的东西可能会导致这种情况，但在我的代码中找不到问题所在。

问题出现在

file['player'] = player

玩家是类实体：

player = entity(y,x, '@', 200, False)

这是类实体的代码：

class entity:
def __init__(self, y, x, ch, speed, ai=True):
    self.y = y
    self.x = x
    self.ch = ch
    self.speed = speed
    self.ai = ai


    self.ap = 0
    self.current_action = {'action': self.wait, 'cost': self.speed}
    self.my_turn = False

def draw(self):
    world[self.y][self.x].walkable = False
    gamepad.addch(self.y, self.x, self.ch)

def take_turn(self):

    self.my_turn = True
    cost = self.current_action['cost']
    self.current_action['action']()

    return cost
def move(self, dy, dx):

    if self.my_turn == False:
        self.current_action = {'action': partial(self.move, dy,dx), 'cost':200}
        deck.append(self)

    if self.my_turn == True:

        #p = previous
        py = self.y
        px = self.x


        pt = world[py][px]
        #Paint previous ground tile
        pt.walkable = True
        gamepad.addch(pt.y,pt.x,pt.ch)

        if world[dy][dx].walkable == True:
            self.y = dy
            self.x = dx
            world[dy][dx].walkable = False

        if self.ai == False:
            draw_map(self.y,self.x)


        self.my_turn = False
    return self.y,self.x

def wait(self):
    self.current_action = {'action': self.wait, 'cost': self.speed}
def drunk_move(self):
    dy = self.y + random.randint(-1,1)
    dx = self.x + random.randint(-1,1)
    self.move(dy, dx)
def ai_simple(self):

    #Figure out if player is higher or not:
    wherey = self.y - player.y
    if wherey > 0:
        dy = self.y-1
    else:
        dy = self.y+1

    wherex = self.x - player.x
    if wherex > 0:
        dx = self.x-1
    else:
        dx = self.x+1

    self.move(dy, dx)

---

在发布这篇文章之前，我试着对pudb做最后一次检查-我也发现了一个错误

file['world'] = world

六

│  File "/usr/lib/python3.3/shelve.py", line 124, in                    │
│__setitem__                                                            │
│    p.dump(value)                                                      │         
│_pickle.PicklingError: Can't pickle <class                             │
│'__main__.tile'>: attribute lookup __main__.tile failed                │

（在运行没有pudb的代码时不显示）

这就是世界：

world = [[ tile(yy,xx,True,'.')
    for xx in range(WORLD_WIDTH) ]
        for yy in range(WORLD_HEIGHT) ]

这是类平铺：

class tile:
def __init__(self,y,x,walkable,ch):
    self.x = x
    self.y = y
    self.walkable = walkable
    self.ch = ch

最后，这是调用shelve的完整函数：

def save_game():
    file = shelve.open('savegame', 'n')
    file['world'] = world
    file['player']= player

    file.close()

我相信这是所有相关的代码。

是什么导致了这些错误？

Answer 1

第一个问题是由实体类中的这一行引起的：

self.current_action = {'action': self.wait, 'cost': self.speed}

current_action包含对绑定方法的引用，这些方法无法进行pickle。你可以使用^{}和^{}来改变你的pickling行为，这样你在pickling时就不会pickle方法，而是pickle方法的名称（或者在分配了partial对象的情况下是名称和参数），并在取消pickling时恢复该值。

我不太确定您的第二个问题，但如果只在调试器中运行它，那么可能是调试器如何加载__main__模块的问题。您可以尝试将您的__main__块移到另一个模块中，然后从该模块导入并打开您的代码。有时候这可以解决这些问题。