Q:

Python's pathlib get parent's relative path

Consider the following Path:
import pathlib
path = pathlib. Path(r'C:\users\user1\documents\importantdocuments')

How can I extract the exact string 'documents\importantdocuments' from that Path? 
I know this example looks silly, the real context here is translating a local file to a remote download link. 

A:

Use the PurePath.relative_to() method to produce a relative path. 
You weren't very clear as to how the base path is determined; here are two options:
secondparent = path.parent.parent
homedir = pathlib. Path(r'C:\users\user1')

then just use str() on the path.relative_to(secondparent) or path.relative_to(homedir) result. 
Demo:
>>> import pathlib
>>> path = pathlib. Path(r'C:\users\user1\documents\importantdocuments')
>>> secondparent = path.parent.parent
>>> homedir = pathlib. Path(r'C:\users\user1')
>>> str(path.relative_to(secondparent))
'documents\\importantdocuments'
>>> str(path.relative_to(homedir))
'documents\\importantdocuments'

