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Extract file name from path, no matter what the os/path format

python
filename-extraction
pathlib
cross-platform
Anton ShumikhinbyAnton Shumikhin·Aug 6, 2024
TLDR

To extract the filename from a path on any OS, use the os.path functions, specifically os.path.basename combined with os.path.normpath:

import os filename = os.path.basename(os.path.normpath('/any/os/path/to/file.txt')) # Can you feel the zen of Python? print(filename) # This will output: file.txt

Tactics for extracting filenames

Facing a file path and need to wrestle out the filename? Here are some strategies to help Python be your stalwart companion and win the day.

Cross-platform filename extraction with ntpath

If os.path.basename fails to impress, an alternative solution comes with ntpath.basename. It performs well in extracting filenames across different OS path formats, like a ninja approaching from the shadows:

import ntpath filename = ntpath.basename('/any/os/path\\to\\file.txt') # Fun fact: ntpath loves both kinds of slashes print(filename) # Should print: file.txt

A sophisticated approach with pathlib

If you're using Python 3.4 or above, consider pathlib. It's not your grandma's path manager and offers a simplified and more versatile method for dealing with paths:

from pathlib import Path filename = Path("/any/os/path/to/file.txt").name # .name is such a sweet function name, isn't it? print(filename) # The name of our precious: file.txt

The pathlib.Path.name method is consistent, even when faced with trailing separators or a salad of path separators.

The consistent path_leaf function

Crafting a custom function, such as path_leaf, ensures reliable filename retrieval no matter the slashes, separators, or trailing quirks:

import os import ntpath def path_leaf(path): head, tail = ntpath.split(path) # heads or tails? We want tails this time! return tail or ntpath.basename(head) # tail or basename. A pythonic conundrum. print(path_leaf('/path/to/file.txt')) # Places everyone, big reveal: file.txt print(path_leaf('C:\\path\\to\\file.txt')) # Once more with feeling: file.txt

This function uses ntpath.basename as a fallback, proving two heads are better than one when isolating filenames.

Dancing around cross-platform issues

When extracting filenames, being aware of cross-platform issues is crucial. The devil is in the details, especially when it comes to mix matching separators and paths from foreign operating systems. Remember: endorsed by Guido himself, Python is born to handle such varieties. Test your path manipulations on diverse path scenarios for the best performance.

Minding the separators

Separators in file paths can be a real spanner 🛠 in your works. ntpath to the rescue for consistent file name extraction from different OS path formats. It’s like having a translator which speaks Windows and Unix. 🌐

Handling trailing separators and relative paths

When wrestling with trailing slashes or relative paths, os.path.split is the go-to function. It'll chip away the filename as tail and leave the remaining path as head:

head, tail = os.path.split('/path/to/directory/') # head is '/path/to/directory', tail is ''

Pouring some path_leaf or pathlib magic sauce can prevent the tail from eluding capture.