Python · Serialization: pickle, JSON & CSV

After a JSON round-trip, what Python type do you get back for a JSON number like 12, a number like 12.34, true, and null?

Answer locked. Get the free KnowCard app to reveal it — plus spaced-repetition review so it actually sticks.

This is one card from the KnowCard library — thousands more across SAP, Linux, Python and more. In the app you get the answer, AI explanations, and cards that come back right before you would forget them. Free to start on iOS, Android or the web.

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?

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

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?

Start learning today

Free to start — download the app or use it in your browser.