Strings, Serialization, and File Paths

Before we get involved with higher-level design patterns, let's take a deep dive into one of Python's most common objects: the string. We'll see that there is a lot more to the string than meets the eye, and we'll also cover searching strings for patterns, and serializing data for storage or transmission.

All of these topics are elements of making objects persistent. Our application can create objects in files for use at a later time. We often take persistence – the ability to write data to a file and retrieve it at an arbitrary later date – for granted. Because persistence happens via files, at the byte level, via OS writes and reads, it leads to two transformations: data we have stored must be decoded into a nice, useful object collection of objects in memory; objects from memory need to be encoded to some kind of clunky text or bytes format for storage, transfer over the network, or remote invocation on...