Python:使用pickle模块保存和加载对象时出错 [英] Python: Errors saving and loading objects with pickle module

问题描述

我正在尝试用这段代码加载和保存对象，这是我从一个星期前问的一个问题得到的:

I am trying to load and save objects with this piece of code I get it from a question I asked a week ago: Python: saving and loading objects and using pickle.

这段代码是这样的:

class Fruits: pass

banana = Fruits()    
banana.color = 'yellow'     
banana.value = 30

import pickle

filehandler = open("Fruits.obj","wb")    
pickle.dump(banana,filehandler)    
filehandler.close()

file = open("Fruits.obj",'rb')    
object_file = pickle.load(file)    
file.close()

print(object_file.color, object_file.value, sep=', ')

乍一看，这段代码可以很好地工作，可以加载并查看已保存对象的颜色"和值". 但是，我追求的是关闭一个会话，打开一个新会话，然后加载我在上一个会话中保存的内容.在行filehandler.close()之后关闭会话，然后打开一个新的行，然后放置其余的代码，然后在object_file = pickle.load(file)之后输入以下错误:

At a first glance the piece of code works well, getting load and see the 'color' and 'value' of the saved object. But, what I pursuit is to close a session, open a new one and load what I save in a past session. I close the session after putting the line filehandler.close() and I open a new one and I put the rest of your code, then after putting object_file = pickle.load(file) I get this error:

Traceback (most recent call last): 
File "<pyshell#5>", line 1, in <module> 
object_file = pickle.load(file) 
File "C:\Python31\lib\pickle.py", line 1365, in load 
encoding=encoding, errors=errors).load() 
AttributeError: 'module' object has no attribute 'Fruits' 

任何人都可以向我解释此错误消息的含义，并告诉我如何解决此问题吗?

Can anyone explain me what this error message means and telling me how to solve this problem?

非常感谢，新年快乐！

推荐答案

Python不会腌制整个类.只有名字.因此，您必须将包含它们的模块保存到文件中，并且在取消它们腌制时可以导入.然后，Python将重新导入它们.

Python does not pickle whole classes. Only the names. Therefore you must have the module that contains them saved to a file and importable at the time they are unpickled. Python will then re-import them.

如果遇到问题，则可能需要定义用于腌制的特殊辅助方法__getstate__和__setstate__.

If you run into problems, you may need to define special helper methods, __getstate__ and __setstate__ that are used for pickling.

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