How to get only the last part of a path in Python?

With python 3 you can use the pathlib module (pathlib.PurePath for example):

>>> import pathlib

>>> path = pathlib.PurePath('/folderA/folderB/folderC/folderD/')
>>> path.name
'folderD'

If you want the last folder name where a file is located:

>>> path = pathlib.PurePath('/folderA/folderB/folderC/folderD/file.py')
>>> path.parent.name
'folderD'

I like the parts method of Path for this:

grandparent_directory, parent_directory, filename = Path(export_filename).parts[-3:]
log.info(f'{t: <30}: {num_rows: >7} Rows exported to {grandparent_directory}/{parent_directory}/{filename}')

If you use the native python package pathlib it's really simple.

>>> from pathlib import Path
>>> your_path = Path("/folderA/folderB/folderC/folderD/")
>>> your_path.stem
'folderD'

Suppose you have the path to a file in folderD.

>>> from pathlib import Path
>>> your_path = Path("/folderA/folderB/folderC/folderD/file.txt")
>>> your_path.name
'file.txt'
>>> your_path.parent
'folderD'

During my current projects, I'm often passing rear parts of a path to a function and therefore use the Path module. To get the n-th part in reverse order, I'm using:

from typing import Union
from pathlib import Path

def get_single_subpath_part(base_dir: Union[Path, str], n:int) -> str:
    if n ==0:
        return Path(base_dir).name
    for _ in range(n):
        base_dir = Path(base_dir).parent
    return getattr(base_dir, "name")

path= "/folderA/folderB/folderC/folderD/"

# for getting the last part:
print(get_single_subpath_part(path, 0))
# yields "folderD"

# for the second last
print(get_single_subpath_part(path, 1))
#yields "folderC"

Furthermore, to pass the n-th part in reverse order of a path containing the remaining path, I use:

from typing import Union
from pathlib import Path

def get_n_last_subparts_path(base_dir: Union[Path, str], n:int) -> Path:
    return Path(*Path(base_dir).parts[-n-1:])

path= "/folderA/folderB/folderC/folderD/"

# for getting the last part:
print(get_n_last_subparts_path(path, 0))
# yields a `Path` object of "folderD"

# for second last and last part together 
print(get_n_last_subparts_path(path, 1))
# yields a `Path` object of "folderc/folderD"

Note that this function returns a Pathobject which can easily be converted to a string (e.g. str(path))