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Unify Path Manipulation with pathlib

As the official documentation of pathlib said,

The pathlib module offers classes representing filesystem paths with semantics appropriate for different operating systems.

It manipulates filesystem paths in an object-oriented way, which is more well-organized in my opinion.

Table of Content

Comparison

Error Prone

dir_path = 'data/test/'
file_path = dir_path + 'raw.txt'                  # 'data/test/raw.txt'
file_name = file_path.split('/')[-1]              # 'raw.txt'
dir_path = file_path.rsplit('/', maxsplit=1)[0]   # 'data/test'
file_ext = file_name.split('.')[-1]               # 'txt'
file_stem = file_name.rsplit('.', maxsplit=1)[0]  # 'raw'
if os.path.exists(file_path):
    with open(file_path) as f:
        print(f.read())

Old Way with os.path

import os
dir_path = os.path.join('data', 'test')
file_path = os.path.join(dir_path, 'raw.txt')     # 'data/test/raw.txt'
file_name = os.path.basename(file_path)           # 'raw.txt'
dir_path = os.path.dirname(file_path)             # 'data/test'
file_ext = file_name.split('.')[-1]               # 'txt'
file_stem = file_name.rsplit('.', maxsplit=1)[0]  # 'raw'
if os.path.exists(file_path):
    with open(file_path) as f:
        print(f.read())

New Way with pathlib

from pathlib import Path
dir_path = Path('data/test')
file_path = dir_path / 'raw.txt'  # 'data/test/raw.txt'
file_name = file_path.name        # 'raw.txt'
file_name = file_path.parts[-1]   # 'raw.txt'
dir_path = file_path.parent       # Path('data/test')
file_ext = file_path.suffix       # '.txt'
file_stem = file_path.stem        # 'raw'
absolute_path = file_path.resolve()  # '/home/xxx/data/test/raw.txt', but file_path is still 'data/test/raw.txt'
if file_path.exists():
    with open(file_path) as f:    # ==> with file_path.open() as f:
        print(f.read())

More examples of pathlib

In Python 3.4, pathlib became part of the standard library. For Python 3.3 and earlier, pip install pathlib would be needed.

from pathlib import Path

# Create path from string
a = Path('data/test/raw.txt')

# Existing path
a = Path.cwd()   # Current working directory
a = Path.home()  # Home directory: '~'

# Create path from parts
a = Path.home() / 'data' / 'test' / 'raw.txt'
a = Path.home().joinpath('data', 'test', 'raw.txt')  # Equivalent to the above
b = a.parent.parent / 'train' / 'raw.txt'  # 'data/train/raw.txt'

# Create new path from old one
b = a.with_suffix('.py')  # 'data/test/raw.py'

# Read file
with a.open() as f:
    print(f.read())
# Or directly handle file opening and closing internally by Path's method
print(a.read_text())

# Move raw.txt to raw.py
a.replace(a.with_suffix('.py'))

# Remove file
a.unlink()

# Remove dir
a.parent.rmdir()

# Iterate through files
d = [f for f in Path.cwd().iterdir()]      # Similar results of shell command `ls` without '.' and '..'
d = [f for f in Path.cwd().glob('*.py')]   # ls *.py
d = [f for f in Path.cwd().rglob('*.py')]  # find . -name *.py

Reference