pickle

问题 I'm using the shelve module with gdbm to store Python objects. I understand that shelve uses pickle to store the objects. Unfortunately, the sizes of my shelves are too large. I found this solution to bzip2 or gzip individual pickles. My question is: is there a way to make shelve compress all its pickles? 来源： https://stackoverflow.com/questions/53990501/reduce-python-shelve-size

问题 I'm using the shelve module with gdbm to store Python objects. I understand that shelve uses pickle to store the objects. Unfortunately, the sizes of my shelves are too large. I found this solution to bzip2 or gzip individual pickles. My question is: is there a way to make shelve compress all its pickles? 来源： https://stackoverflow.com/questions/53990501/reduce-python-shelve-size

问题 I'm using the shelve module with gdbm to store Python objects. I understand that shelve uses pickle to store the objects. Unfortunately, the sizes of my shelves are too large. I found this solution to bzip2 or gzip individual pickles. My question is: is there a way to make shelve compress all its pickles? 来源： https://stackoverflow.com/questions/53990501/reduce-python-shelve-size

问题 I am trying to pickle a dynamically generated class as a factory for an alternative class. Something like the following: import sys, pickle class BC(object): pass C = type("NewClassName", (BC,), {}) pickle.dump(C, sys.stdout) This leads to the following error: pickle.PicklingError: Can't pickle <class '__main__.NewClassName'>: it's not found as __main__.NewClassName For pickling an object of a dynamically generated class, you can define an __reduce__ method, but is there a way to achieve this

问题 I am trying to pickle a dynamically generated class as a factory for an alternative class. Something like the following: import sys, pickle class BC(object): pass C = type("NewClassName", (BC,), {}) pickle.dump(C, sys.stdout) This leads to the following error: pickle.PicklingError: Can't pickle <class '__main__.NewClassName'>: it's not found as __main__.NewClassName For pickling an object of a dynamically generated class, you can define an __reduce__ method, but is there a way to achieve this

问题 Assume that I have a pickle dump - either as a file or just as a string - how can I determine the protocol that was used to create the pickle dump automatically? And if so, do I need to read the entire dump to figure out the protocol or can this be achieved in O(1)? By O(1) I think about some header information at the beginning of the pickle string or file whose read out does not require processing the whole dump. Thanks a lot! EDIT: I have an update on this, apparently the answer given below

问题 Assume that I have a pickle dump - either as a file or just as a string - how can I determine the protocol that was used to create the pickle dump automatically? And if so, do I need to read the entire dump to figure out the protocol or can this be achieved in O(1)? By O(1) I think about some header information at the beginning of the pickle string or file whose read out does not require processing the whole dump. Thanks a lot! EDIT: I have an update on this, apparently the answer given below

问题 Assume that I have a pickle dump - either as a file or just as a string - how can I determine the protocol that was used to create the pickle dump automatically? And if so, do I need to read the entire dump to figure out the protocol or can this be achieved in O(1)? By O(1) I think about some header information at the beginning of the pickle string or file whose read out does not require processing the whole dump. Thanks a lot! EDIT: I have an update on this, apparently the answer given below

问题 Not able to load a pickle file. I am using python 3.5 import pickle data=pickle.load(open("D:\\ud120-projects\\final_project\\final_project_dataset.pkl", "r")) TypeError: a bytes-like object is required, not 'str' . . Also tried: import pickle data=pickle.load(open("D:\\ud120-projects\\final_project\\final_project_dataset.pkl", "rb")) UnpicklingError: the STRING opcode argument must be quoted . . Same errors even when using with statements import pickle with open("D:\\ud120-projects\\final

问题 Not able to load a pickle file. I am using python 3.5 import pickle data=pickle.load(open("D:\\ud120-projects\\final_project\\final_project_dataset.pkl", "r")) TypeError: a bytes-like object is required, not 'str' . . Also tried: import pickle data=pickle.load(open("D:\\ud120-projects\\final_project\\final_project_dataset.pkl", "rb")) UnpicklingError: the STRING opcode argument must be quoted . . Same errors even when using with statements import pickle with open("D:\\ud120-projects\\final