python pickle.dumps AssertionError [英] python pickle.dumps AssertionError

问题描述

我正在尝试腌制包含两个其他实例列表的类实例.两个列表中的实例具有互相引用的实例的属性.这是课程.

I'm trying to pickle a class instance containing two lists of another instances. The instances in the two lists have attributes that refer instances of each other. Here are the classes.

import pickle
from copy import copy

class Graph:
    def __init__(self):
        self.vertices = {}
        self.edges = set()
    def __repr__(self):
        return "\n".join(map(str, sorted(self.vertices, key=lambda v:v.id)))

class Edge:
    def __init__(self, vfrom, vto):
        self.vfrom = vfrom
        self.vto = vto
    def __hash__(self):
        return hash((self.vto, self.vfrom))
    def __repr__(self):
        return str(self.vto.id)
    def __getstate__(self):
        vfrom = copy(self.vfrom)
        vfrom.del_outgoing(self)
        vto = copy(self.vto)
        vto.del_incoming(self)
        self.__dict__.update({"vfrom":vfrom, "vto":vto, })
        return self.__dict__
    def __setstate__(self, state):
        self.__dict__.update(state)
        self.__dict__["vfrom"].add_outgoing(self)
        self.__dict__["vto"].add_incoming(self)

class Vertex:
    def __init__(self, id):
        self.id = id
        self.incoming = set()
        self.outgoing = set()
    def __repr__(self):
        return "Vertex %d -> %s"%(self.id, ", ".join(map(str, self.outgoing)))
    def __hash__(self):
        return hash(self.id)
    def add_incoming(self, edge):
        if not edge in self.incoming:
            self.incoming.add(edge)
    def add_outgoing(self, edge):
        if not edge in self.outgoing:
            self.outgoing.add(edge)
    def del_incoming(self, edge):
        self.incoming.discard(edge)
    def del_outgoing(self, edge):
        self.outgoing.discard(edge)

当我按如下所示对一个简单的图进行腌制时，出现了AssertionError.

I got an AssertionError when I pickled a simple graph as follows.

>>> v0 = Vertex(0)
>>> v1 = Vertex(1)
>>> e0to1 = Edge(v0, v1)
>>> v0.add_outgoing(e0to1)
>>> v1.add_incoming(e0to1)
>>> g = Graph()
>>> g.vertices[v0] = v0
>>> g.vertices[v1] = v1
>>> g.edges.add(e0to1)
>>> g.edges.add(e0to1)
>>> v2 = Vertex(2)
>>> e0to2 = Edge(v0, v2)
>>> v0.add_outgoing(e0to2)
>>> v2.add_incoming(e0to2)
>>> g.vertices[v2] = v2
>>> g.edges.add(e0to2)
>>> 
>>> print g
Vertex 0 -> 2, 1
Vertex 1 -> 
Vertex 2 -> 
>>> p = pickle.dumps(g)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python2.6/pickle.py", line 1366, in dumps
    Pickler(file, protocol).dump(obj)
  File "/usr/lib/python2.6/pickle.py", line 224, in dump
    self.save(obj)
  File "/usr/lib/python2.6/pickle.py", line 286, in save
    f(self, obj) # Call unbound method with explicit self
  File "/usr/lib/python2.6/pickle.py", line 725, in save_inst
    save(stuff)
  File "/usr/lib/python2.6/pickle.py", line 286, in save
    f(self, obj) # Call unbound method with explicit self
  File "/usr/lib/python2.6/pickle.py", line 649, in save_dict
    self._batch_setitems(obj.iteritems())
  File "/usr/lib/python2.6/pickle.py", line 663, in _batch_setitems
    save(v)
  File "/usr/lib/python2.6/pickle.py", line 331, in save
    self.save_reduce(obj=obj, *rv)
  File "/usr/lib/python2.6/pickle.py", line 401, in save_reduce
    save(args)
  File "/usr/lib/python2.6/pickle.py", line 286, in save
    f(self, obj) # Call unbound method with explicit self
  File "/usr/lib/python2.6/pickle.py", line 562, in save_tuple
    save(element)
  File "/usr/lib/python2.6/pickle.py", line 286, in save
    f(self, obj) # Call unbound method with explicit self
  File "/usr/lib/python2.6/pickle.py", line 600, in save_list
    self._batch_appends(iter(obj))
  File "/usr/lib/python2.6/pickle.py", line 615, in _batch_appends
    save(x)
  File "/usr/lib/python2.6/pickle.py", line 286, in save
    f(self, obj) # Call unbound method with explicit self
  File "/usr/lib/python2.6/pickle.py", line 725, in save_inst
    save(stuff)
  File "/usr/lib/python2.6/pickle.py", line 286, in save
    f(self, obj) # Call unbound method with explicit self
  File "/usr/lib/python2.6/pickle.py", line 649, in save_dict
    self._batch_setitems(obj.iteritems())
  File "/usr/lib/python2.6/pickle.py", line 663, in _batch_setitems
    save(v)
  File "/usr/lib/python2.6/pickle.py", line 286, in save
    f(self, obj) # Call unbound method with explicit self
  File "/usr/lib/python2.6/pickle.py", line 725, in save_inst
    save(stuff)
  File "/usr/lib/python2.6/pickle.py", line 286, in save
    f(self, obj) # Call unbound method with explicit self
  File "/usr/lib/python2.6/pickle.py", line 649, in save_dict
    self._batch_setitems(obj.iteritems())
  File "/usr/lib/python2.6/pickle.py", line 663, in _batch_setitems
    save(v)
  File "/usr/lib/python2.6/pickle.py", line 331, in save
    self.save_reduce(obj=obj, *rv)
  File "/usr/lib/python2.6/pickle.py", line 405, in save_reduce
    self.memoize(obj)
  File "/usr/lib/python2.6/pickle.py", line 244, in memoize
    assert id(obj) not in self.memo
AssertionError

删除v2后，我开始工作.

I worked when the v2 is removed.

>>> v0 = Vertex(0)
>>> v1 = Vertex(1)
>>> e0to1 = Edge(v0, v1)
>>> v0.outgoing.add(e0to1)
>>> v1.incoming.add(e0to1)
>>> g = Graph()
>>> g.vertices[v0] = v0
>>> g.vertices[v1] = v1
>>> g.edges.add(e0to1)
>>> g.edges.add(e0to1)
>>> import cPickle as pickle
>>> p = pickle.dumps(g)
>>> print pickle.loads(p)
Vertex 0 -> 1
Vertex 1 -> 

你有什么主意吗?

推荐答案

旧的pickle协议无法处理某些数据.要解决您的问题，请使用pickle.HIGHEST_PROTOCOL

There are some kinds of data the older pickle protocol cannot handle. To solve your problem, use pickle.HIGHEST_PROTOCOL

>>> p = pickle.dumps(g)
  File "/usr/lib/python2.6/pickle.py", line 244, in memoize
    assert id(obj) not in self.memo
AssertionError:
>>> p = pickle.dumps(g, pickle.HIGHEST_PROTOCOL)
>>> # No problem!

这篇关于python pickle.dumps AssertionError的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！