pathlib: Paths as Objects

Beginner file code glues strings with / or os.path.join. pathlib treats a path as an object with behavior:

from pathlib import Path

data_dir = Path("data")
config = data_dir / "settings.json"     # / operator joins safely
config.name          # "settings.json"
config.stem          # "settings"
config.suffix        # ".json"
config.parent        # data
config.exists()

The Killer Features:

data_dir.mkdir(parents=True, exist_ok=True)   # idempotent directory creation
for csv_file in data_dir.glob("*.csv"):       # pattern matching, lazy iterator
    print(csv_file)

text = config.read_text(encoding="utf-8")     # quick read (small files!)
config.write_text("{}", encoding="utf-8")     # quick write

Path safety habits

• Never trust user-supplied paths. Path(user_input).resolve() then verify it's inside the directory you expect — otherwise ../../etc/passwd walks out of your sandbox. That's path traversal, and it's module 11's audit topic too.
• Pass encoding= on every text read/write. The default encoding varies by platform; explicit UTF-8 is the portability contract.
• resolve() turns relative into absolute (and collapses ..) — normalize first, compare after.