Path Manipulations

Get path of the current script

import pathlib
script_path = pathlib.Path(__file__)

Get path of the python interpreter

import sys
interp_path = sys.executable

Get Current Working Directory

import os
interp_path = os.getcwd()

Change Working Directory

import os
interp_path = os.chdir("/new/working/directory")

Get absolute path

import pathlib
rel_p = pathlib.Path("./relative/path")
abs_p = rel_p.resolve()

Important

Current working directory is used to resolve the absolute path. This will work even if the path does not exist.

Get parent path

import pathlib
p = pathlib.Path("./path/file.txt")
p.parent # PosixPath('./path')
p.parent.parent # PosixPath('.')

# If you want to go further you need to transform to the absolute path first
# Example if the working directory is "/home/username/work"
p.resolve().parent.parent.parent # PosixPath('/home/username/work')

Join path

import pathlib
p = pathlib.Path("yo/hey")
p = pathlib.Path(p, 'dir', 'hehe/hihi', 'file_name')
# p = PosixPath('yo/hey/dir/hehe/hihi/file_name')

Check if the path is an existing file/folder

import pathlib
pathlib.Path("/path/to/file.txt").is_file() # boolean
pathlib.Path("/path/to/file.txt").is_dir() # boolean

Create a directory even if it already exists

import os
os.makedirs("hi/how/are/you", exist_ok=True)

Get extension

import pathlib
ext = pathlib.Path("/path/to/file.TXT").suffix.lower() # ext = ".txt"

Get string filepath from a pathlib.Path object

import pathlib
path_str = pathlib.Path("/path/to/file.txt").as_posix() # "/path/to/file.txt"

Iterate over all files in a folder

import os
import pathlib

# Not recursive: Only the files contain in the specified folder
for filename in os.listdir('.'):
    p = pathlib.Path('.', filename)
    if p.is_file():
        print(p)

# Recursively: All files including sub-directories
for root, dirs, files in os.walk('.'):
    for filename in files:
        # Filepath
        p = pathlib.Path(root, filename)
        print(p)

Resolve path using pattern expansion (“?”, “*”, “[]”, “**”) using glob

import glob

list_filepaths = glob.glob("path_?/with/**/patterns/*.txt")

Example - Typical use case

The user inputs a path:

If the path has an extension: we create the directory if it doesn’t exist and the file
If the path don’t have extension, 2 options:
- EITHER: we consider the path as a file path without extension: we add the extension ourself
- OR: we consider the path as a directory path: we add the filename and extension ourself

import argparse
import pathlib
import os

parser = argparse.ArgumentParser(
    description="Description of the program",
    formatter_class=argparse.RawTextHelpFormatter,
)
# Positional string Argument
parser.add_argument("path", type=str,
    help="Input path")

args = parser.parse_args()

path = args.path

filepath = None
suffix = pathlib.Path(path).suffix.lower()
if suffix == ".txt":
    # The input path is a correct filepath with the expected extension
    filepath = pathlib.Path(path)
elif suffix != "":
    raise ValueError("Invalid file extension")
else:
    # If we consider the path as a directory
    # We add the file name and its extension
    filepath = pathlib.Path(path, "output.txt")
    # If we consider the path as a filename without extension
    # We add the file name and its extension
    filepath = pathlib.Path(path + ".txt")

# Creating the directory if it doesn't exist
os.makedirs(filepath.parent.as_posix(), exists_ok=True)

Sources:

Glob: https://docs.python.org/3/library/glob.html