Pathlib and OS Path module in Python

Posted under » Python » Django on 24 Mar 2026

In Django, on the settings file we will see pathlib in action.

from pathlib import Path
# Build paths inside the project like this: BASE_DIR / 'subdir'.
BASE_DIR = Path(__file__).resolve().parent.parent

In this case, __file__ is actually located at your django app location.

The pathlib module in Python provides an object-oriented way to work with filesystem paths. Unlike traditional os.path which treats paths as plain strings, pathlib represents them as objects, making operations like path joining, file reading/writing and checking existence much cleaner and cross-platform.

To view or list all subdirectories within a given directory, use iterdir() method and filter results using .is_dir(). Below we list all the subdirectories under the root folder = /.

from pathlib import Path
p = Path('/')
for subdir in p.iterdir():
    if subdir.is_dir():
        print(subdir)

With OS path, you can set your basename any name even if the actual dir or path does not exist in the system.

# basename function
import os
out = os.path.basename("/baze/folio")
print(out)

os.path.isdir(path) function specifies whether the path is existing directory or not.

# isdir function
import os
out = os.path.isdir("/baze/folio")
print(out)

True

Now back to pathlib, to find all text files (.txt) within a folder and its subfolders, use rglob() method from pathlib. It performs a recursive search, making it easy to scan entire directory trees for specific file types.

from pathlib import Path
p = Path('/baze/folio')
files = p.rglob('*.txt')
for f in files:
    print(f)
    
/baze/folio/img/README.txt
/baze/folio/js/vendor/jquery/LICENSE.txt
/baze/folio/js/vendor/xregexp/LICENSE.txt

pathlib makes directory navigation simple by overloading / operator. This allows you to join paths cleanly and create new Path objects without using manual string concatenation. This eg. code joins an existing path with "README.txt" to create a new path object.

sp = p / 'README.txt'
print(sp)
# Check if the path is absolute
print("Is absolute:", sp.is_absolute())
# Get the file name
print("File name:", sp.name)
# Get the extension
print("Extension:", sp.suffix)
# Get the parent directory
print("Parent directory:", sp.parent)

You will get this output

/baze/folio/img/README.txt
Is absolute: True
File name: README.txt
Extension: .txt
Parent directory: /baze/folio/img/img

pathlib makes file handling easy by allowing you to open, read and write files directly through Path objects no need for manual path strings or separate functions.

Example: This code reads overwrite "try write this text" into output.txt. Followed by appending "try write another line". Finally read content from README.txt

# old text will be overwritten
with (p / 'README.txt').open('w') as file:
    file.write("let us write this text")

# appending to a file
with (p / 'README.txt').open('a') as file:
    file.write("let us write another line")

with (p / 'README.txt').open('r') as file:
    content = file.read()
    print(content)

let us write this text
let us write another line

Not to be mistaken with PYTHONPATH