Persisting data on disk

In the last section of this chapter, we're exploring how to persist data on disk in three different formats. We will explore pickle, shelve, and a short example that will involve accessing a database using SQLAlchemy, the most widely adopted ORM library in the Python ecosystem.

Serializing data with pickle

The pickle module, from the Python standard library, offers tools to convert Python objects into byte streams, and vice versa. Even though there is a partial overlap in the API that pickle and json expose, the two are quite different. As we have seen previously in this chapter, JSON is a text format, human readable, language independent, and supports only a restricted subset of Python data types. The pickle module, on the other hand, is not human readable, translates to bytes, is Python specific, and, thanks to the wonderful Python introspection capabilities, it supports an extremely large amount of data types.

Regardless of these differences, though, which you should...