Python · Serialization: pickle, JSON & CSV

Which serializer should you reach for: arbitrary Python objects (custom classes, sets, tuples) to a local cache file, same Python program reads it back?

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More in Serialization: pickle, JSON & CSV

What is the difference between pickle.dump / load and pickle.dumps / loads?

A web server unpickles a session blob that arrived from the client. A security reviewer flags it immediately. Why?

You pickle an object to a file, then a colleague tries to load it and gets an UnpicklingError. The data file is intact. What's the likely cause?

What's wrong with this pickle code? ``` with open("data.pkl", "w") as f: pickle.dump(obj, f) ```

You dump three objects to one file with three pickle.dump calls. How do you read all three back?

What does this print? ``` import json s = json.dumps({1: "a", 2: "b"}) d = json.loads(s) print(list(d.keys())) ```

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