How to Auto Organize Downloads by File Extension in Python

import os
import shutil
from pathlib import Path

def organize_downloads(download_dir="~/Downloads"):
    """Move files in a directory into subfolders based on file extension."""
    download_path = Path(download_dir).expanduser()
    
    if not download_path.exists():
        print(f"Directory not found: {download_path}")
        return

    for item in download_path.iterdir():
        if item.is_file():
            ext = item.suffix.lower() or "no_extension"
            ext_folder = ext.lstrip(".") + "_files"
            target_dir = download_path / ext_folder
            target_dir.mkdir(exist_ok=True)
            
            target_path = target_dir / item.name
            if not target_path.exists():
                shutil.move(str(item), str(target_path))
                print(f"Moved: {item.name} -> {ext_folder}/{item.name}")
            else:
                print(f"Skipped (already exists): {item.name}")

if __name__ == "__main__":
    # Example: test with a temporary directory
    import tempfile
    with tempfile.TemporaryDirectory() as tmp:
        p = Path(tmp)
        (p / "report.pdf").write_text("PDF content")
        (p / "image.png").write_bytes(b"\x89PNG\r\n")
        (p / "notes.txt").write_text("Hello")
        (p / "README").write_text("No extension")
        
        organize_downloads(tmp)
        print("\nOrganized structure:")
        for dirpath, dirnames, filenames in os.walk(tmp):
            for name in filenames:
                print(os.path.relpath(os.path.join(dirpath, name), tmp))