Using pathlib to work with filenames

Most operating systems use a hierarchical path to identify a file. Here's an example filename, including the entire path:

/Users/slott/Documents/Writing/Python Cookbook/code

This full pathname has the following elements:

• The leading / means the name is absolute. It starts from the root of the directory of files. In Windows, there can be an extra letter in front of the name, such as C:, to distinguish between the directories on individual storage devices. Linux and macOS treat all the devices as a unified hierarchy.
• The names Users, slott, Documents, Writing, Python Cookbook, and code represent the directories (or "folders," as a visual metaphor) of the filesystem. The path names a top-level Users directory. This directory is expected to contain the slot subdirectory. This is true for each name in the path.
• / is a separator between directory names. The Windows OS uses \ to separate items on the...