Why does pathlib have both PurePath & Path?

Question

More than an answer to the question, I am trying to learn how to make sense of the Official Python Documentation.

I understand that Path inherits from PurePath, but I am unable to understand when to use which and why there is PurePath & Path instead of one.

In the list of alternatives, most are suggesting Path while some are suggesting Pathlib.

I am looking at os.path.dirname() where they are suggesting PurePath.parent. But I am getting the same result when I run pathlib.PurePath(file).parent.name & pathlib.Path(file).parent.name.

So, why did they use PurePath for some & Path for most. Why did they not suggest Path.parent instead of PurePath.parent ?

Answer 1

First paragraph in pathlib documentation states:

Path classes are divided between pure paths, which provide purely computational operations without I/O, and concrete paths, which inherit from pure paths but also provide I/O operations.

Pure path objects provide path-handling operations which don’t actually access a filesystem.

Concrete paths are subclasses of the pure path classes. In addition to operations provided by the former(pure path), they also provide methods to do system calls on path objects.

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In conclusion, PurePath acts like string (remove parts of path, join with another path, get parents etc). To remove directory, search directory, create a file or write to file, you must use Path object.