Python: Get relative path from comparing two absolute paths

Question

Say, I have two absolute paths. I need to check if the location referring to by one of the paths is a descendant of the other. If true, I need to find out the relative path

Answer 1

Edit : See jme's answer for the best way with Python3.

Using pathlib, you have the following solution :

Let's say we want to check if son is a descendant of parent, and both are Path objects. We can get a list of the parts in the path with list(parent.parts). Then, we just check that the begining of the son is equal to the list of segments of the parent.

>>> lparent = list(parent.parts)
>>> lson = list(son.parts)
>>> if lson[:len(lparent)] == lparent:
>>> ... #parent is a parent of son :)

If you want to get the remaining part, you can just do

>>> ''.join(lson[len(lparent):])

It's a string, but you can of course use it as a constructor of an other Path object.