Using pathlib in Python 3 to Handle Cross-Platform File Paths

When working with file paths in Python, Windows uses backslashes while most other operating systems use forward slashes, a legacy inconsistency dating back to MS‑DOS.

Hard‑coding path strings leads to bugs on different platforms; Python 3’s pathlib module solves this by providing an object‑oriented interface that automatically uses the correct separator.

Example of the wrong approach using manual string concatenation:

data_folder = "source_data/text_files/"
file_to_open = data_folder + "raw_data.txt"
f = open(file_to_open)
print(f.read())

On Windows, using backslashes can raise FileNotFoundError :

data_folder = "source_data\\text_files\\"
file_to_open = data_folder + "raw_data.txt"
f = open(file_to_open)

The traditional solution is os.path.join() , which builds a path with the appropriate separator, but it can be verbose.

import os.path

data_folder = os.path.join("source_data", "text_files")
file_to_open = os.path.join(data_folder, "raw_data.txt")
f = open(file_to_open)
print(f.read())

The modern and recommended solution is pathlib :

from pathlib import Path

data_folder = Path("source_data/text_files/")
file_to_open = data_folder / "raw_data.txt"
f = open(file_to_open)
print(f.read())

Path objects support many useful operations, such as retrieving the file name, suffix, stem, checking existence, and converting between Unix and Windows formats using PureWindowsPath or Path(...).as_uri() for web links.

from pathlib import Path

filename = Path("source_data/text_files/raw_data.txt")
print(filename.name)
print(filename.suffix)
print(filename.stem)
if not filename.exists():
    print("Oops, file doesn't exist!")
else:
    print("Yay, the file exists!")

Thus, pathlib simplifies cross‑platform file handling and replaces many functions from older modules.