If you’re a Python developer, you might have come across the error “unsupported pickle protocol: 5” while working with pickled objects. This error occurs when you try to load a pickled object that was created using a protocol version that is not supported by the version of Python you’re using.
What are pickled objects?
In Python, pickling is the process of converting an object into a stream of bytes that can be saved to a file, transferred over a network, or stored in a database. Pickled objects can be easily deserialized back into Python objects, allowing you to save and retrieve complex data structures with ease.
What is pickle protocol?
Pickle protocol is the set of rules that govern how a Python object is serialized and deserialized using the pickle module. Each version of Python supports a specific range of pickle protocols, and each protocol has its own strengths and weaknesses.
What causes the “unsupported pickle protocol: 5” error?
The “unsupported pickle protocol: 5” error occurs when you try to load a pickled object that was created using protocol version 5, which was introduced in Python 3.8, into an earlier version of Python that does not support this protocol. This error can also occur if you try to load a pickled object that was created in a higher version of Python into a lower version of Python.
How to fix the “unsupported pickle protocol: 5” error?
The easiest way to fix the “unsupported pickle protocol: 5” error is to upgrade to a version of Python that supports protocol version 5. If you’re unable to upgrade, you can try pickling the object using a lower protocol version that is supported by both the source and destination Python versions. You can do this by specifying the protocol parameter when pickling the object:
import picklewith open("example.pickle", "wb") as f:pickle.dump(example_object, f, protocol=pickle.HIGHEST_PROTOCOL - 1)In this example, we’re pickling the object using the highest protocol version supported by both Python versions minus one.
Conclusion
The “unsupported pickle protocol: 5” error can be a frustrating issue for Python developers, but it can be easily fixed by upgrading to a version of Python that supports the protocol version or by pickling the object using a lower protocol version.