Pickle files in Python3

Question

I've tried to read and load pickle files in Python3.

import pickle as pickle
pickleFileName = 'data/fingerDataSet' + '.pickle'
pickleFile = open(pickleFileName, 'rb')
data = pickle.load(pickleFile)
pickleFile.close()

but in line data = pickle.load(pickleFile) I'm getting strange error UnicodeDecodeError: 'ascii' codec can't decode byte 0xc0 in position 5: ordinal not in range(128)

• Axe319: How was the file written and what did it contain?
• user8408080: In unicode, 0xc0 is the letter À. So the problem should be in the file
• Axe319: I meant more along the lines of what python object was pickled and written to the file?
• Jakub Swistak: I've found some hosting and uploaded file there so uploadfiles.io/90rlmu5d It should be an image of a finger, this works in Python2 so the file is ok.
• Axe319: Unpickling from an untrusted source is a bad idea. Additionally, unpickling data with python 3 that was pickled in python 2 has it's own issues. stackoverflow.com/questions/28218466/…

Answer 1

Pickle is not intended to work across different Python versions. What is likely in this case is that the original data was in a Python 2 str, which contains bytes, and the Python3 version is trying to read it as text, performing an implicit decode.

What you should do there is to unpickle your data in a Python 2 environment, and save it in a way that is not dependente on the Python version (if it is an image, use the PIL library to write a PNG file, for example)