Python - Pickle init 需要 4 个参数 - 给定 1 个

Question

每当我尝试加载 pickle 对象时，都会收到此错误:

I'm sorry, but an uncaught exception occurred.

While running game code:
  File "renpy/common/00action_file.rpy", line 328, in __call__
    renpy.load(fn)
TypeError: __init__() takes exactly 4 arguments (1 given)

-- Full Traceback ------------------------------------------------------------

Full traceback:
  File "renpy/common/_layout/screen_main_menu.rpym", line 29, in script
    $ ui.interact()
  File "/home/digiholic/workspace/SummonerSweetheart-0.9-all/renpy/ast.py", line 785, in execute
    renpy.python.py_exec_bytecode(self.code.bytecode, self.hide, store=self.store)
  File "/home/digiholic/workspace/SummonerSweetheart-0.9-all/renpy/python.py", line 1382, in py_exec_bytecode
    exec bytecode in globals, locals
  File "renpy/common/_layout/screen_main_menu.rpym", line 29, in <module>
    $ ui.interact()
  File "/home/digiholic/workspace/SummonerSweetheart-0.9-all/renpy/ui.py", line 247, in interact
    rv = renpy.game.interface.interact(roll_forward=roll_forward, **kwargs)
  File "/home/digiholic/workspace/SummonerSweetheart-0.9-all/renpy/display/core.py", line 2149, in interact
    repeat, rv = self.interact_core(preloads=preloads, **kwargs)
  File "/home/digiholic/workspace/SummonerSweetheart-0.9-all/renpy/display/core.py", line 2750, in interact_core
    rv = root_widget.event(ev, x, y, 0)
  File "/home/digiholic/workspace/SummonerSweetheart-0.9-all/renpy/display/layout.py", line 846, in event
    rv = i.event(ev, x - xo, y - yo, cst)
  File "/home/digiholic/workspace/SummonerSweetheart-0.9-all/renpy/display/layout.py", line 846, in event
    rv = i.event(ev, x - xo, y - yo, cst)
  File "/home/digiholic/workspace/SummonerSweetheart-0.9-all/renpy/display/layout.py", line 846, in event
    rv = i.event(ev, x - xo, y - yo, cst)
  File "/home/digiholic/workspace/SummonerSweetheart-0.9-all/renpy/display/screen.py", line 626, in event
    rv = self.child.event(ev, x, y, st)
  File "/home/digiholic/workspace/SummonerSweetheart-0.9-all/renpy/display/layout.py", line 846, in event
    rv = i.event(ev, x - xo, y - yo, cst)
  File "/home/digiholic/workspace/SummonerSweetheart-0.9-all/renpy/display/layout.py", line 846, in event
    rv = i.event(ev, x - xo, y - yo, cst)
  File "/home/digiholic/workspace/SummonerSweetheart-0.9-all/renpy/display/layout.py", line 846, in event
    rv = i.event(ev, x - xo, y - yo, cst)
  File "/home/digiholic/workspace/SummonerSweetheart-0.9-all/renpy/display/behavior.py", line 762, in event
    return handle_click(self.clicked)
  File "/home/digiholic/workspace/SummonerSweetheart-0.9-all/renpy/display/behavior.py", line 705, in handle_click
    rv = run(action)
  File "/home/digiholic/workspace/SummonerSweetheart-0.9-all/renpy/display/behavior.py", line 274, in run
    return var(*args, **kwargs)
  File "renpy/common/00action_file.rpy", line 328, in __call__
    renpy.load(fn)
  File "/home/digiholic/workspace/SummonerSweetheart-0.9-all/renpy/loadsave.py", line 573, in load
    roots, log = loads(location.load(filename))
  File "/home/digiholic/workspace/SummonerSweetheart-0.9-all/renpy/loadsave.py", line 51, in loads
    return pickle.loads(s)
  File "/home/tom/ab/x64lucid-deps/install/lib/python2.7/pickle.py", line 1382, in loads
  File "/home/tom/ab/x64lucid-deps/install/lib/python2.7/pickle.py", line 858, in load
  File "/home/tom/ab/x64lucid-deps/install/lib/python2.7/pickle.py", line 1133, in load_reduce
TypeError: __init__() takes exactly 4 arguments (1 given)

Linux-3.11.0-26-generic-x86_64-with-debian-wheezy-sid
Ren'Py 6.18.3.761
Summoner Sweetheart 0.9

我目前正在使用 Renpy，一个 pygame 框架。游戏加载并保存得很好，直到我加载了我编码的外部对象。加载该对象后，pickle 可以很好地保存游戏状态，但无法加载它，从而出现上述错误。

我知道没什么可继续的，但是这个错误超出了我的范围，我什至不知道问题代码可能在哪里。

Answer 1

您没有正确使用__reduce__。参见这里:https://docs.python.org/2/library/pickle.html#object.reduce 。对于类，您可以返回要传递给 __init__ 的 class 和 args 的元组。看到这里https://github.com/uqfoundation/mystic/blob/6bfbc46f9094f96deae020074d7bdad2a43d91d6/mystic/monitors.py#L298举个例子。您还可以使用 __setstate__ 方法来实现更复杂的类行为。

最小示例:

>>> class Foo(object):
...   def __init__(self, x, y, z):
...     self.x = x
...     self.y = y
...     self.z = z
...   def __reduce__(self):
...     return (self.__class__, (self.x, self.y, self.z))
...   f = lambda x:x
... 
>>> f = Foo(1,2,3)
>>> 
>>> import pickle
>>> _f = pickle.loads(pickle.dumps(f))
>>> _f.x, _f.y, _f.z
(1, 2, 3)
>>> 

但是，如果您有很多不可picklable的项目，通常最简单的方法是使用更好的序列化器，例如dill(请参见此处:https://github.com/uqfoundation/dill。