Amit Chaudhary

Posted on Aug 27, 2020 • Updated on Oct 23, 2020 • Originally published at amitness.com

Migrating from OS.PATH to PATHLIB Module in Python

#python #tutorial

In this article, I will go over the most frequent tasks related to file paths and show how you can refactor the old approach of using os.path module to the new cleaner way using pathlib module.

Joining paths

import os
base_path = '/home/ubuntu/'
filename = 'data.csv'
os.path.join(base_path, filename)

In pathlib, we can use the division operator to separate the paths elegantly.

from pathlib import Path
base_path = '/home/ubuntu/'
filename = 'data.csv'
Path(base_path) / filename

Get absolute path

import os
os.path.abspath(__file__)

from pathlib import Path
Path(__file__).resolve()

Get current working directory

import os
os.getcwd()

from pathlib import Path
Path.cwd()

Check if path is a file

import os
os.path.isfile('/home/ubuntu/data.csv')

from pathlib import Path
Path('/home/ubuntu/data.csv').is_file()

Check if path is a directory

import os
os.path.isdir('/home/ubuntu/')

from pathlib import Path
Path('/home/ubuntu/').is_dir()

Check if a path exists

import os
os.path.exists('/home/ubuntu/')

from pathlib import Path
Path('/home/ubuntu/').exists()

Get path to folder containing a file

import os
os.path.dirname('/home/ubuntu/data.csv')
# /home/ubuntu

from pathlib import Path
Path('/home/ubuntu/data.csv').parent
# /home/ubuntu

Get the path to the home directory

import os
os.path.expanduser('~')

from pathlib import Path
Path.home()

Expand the user home directory in a path

import os
os.path.expanduser('~/Desktop')
# '/home/ubuntu/Desktop'

from pathlib import Path
Path('~/Desktop').expanduser()

Get size in bytes of a file

import os
os.path.getsize('/home/ubuntu/data.csv')

from pathlib import Path
Path('/home/ubuntu/data.csv').stat().st_size

Get file extension

import os
path, ext = os.path.splitext('/home/ubuntu/hello.py')
# ('/home/ubuntu/hello', '.py')

from pathlib import Path
Path('/home/ubuntu/hello.py').suffix
# .py

Change permission of a file

import os
os.chmod('key.pem', 0o400)

from pathlib import Path
Path('key.pem').chmod(0o400)

Get file name without directory

import os
os.path.basename('/home/ubuntu/hello.py')
# hello.py

from pathlib import Path
Path('/home/ubuntu/hello.py').name
# hello.py

List contents of a directory

import os
os.listdir()

from pathlib import Path
Path().iterdir()

Create a directory

import os
os.makedirs('/home/ubuntu/data', exist_ok=True)

from pathlib import Path
Path('/home/ubuntu/data').mkdir(exist_ok=True)

Rename files or directories

import os
os.rename('rows.csv', 'data.csv')

from pathlib import Path
Path('rows.csv').rename('data.csv')

Delete a directory

import os
os.rmdir('/home/ubuntu/test')

from pathlib import Path
Path('/home/ubuntu/test').rmdir()

Reading a file

import os
p = os.path.join('/home/ubuntu', 'data.csv')

with open(p) as fp:
    data = fp.read()

In new versions of python, you can directly pass a pathlib Path to the open() function.

from pathlib import Path
path = Path('/home/ubuntu/') / 'data.csv'

with open(path) as fp:
    data = fp.read()

In older versions, you can either convert the path to a string using str() or use the open() method.

from pathlib import Path
path = Path('/home/ubuntu/data.csv')

# Method: 1
data = path.open().read()

# Method 2
with open(str(path)) as fp:
    data = fp.read()

# Method 3
data = path.read_text()

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