07_modules_and_packages.py

"""
Module 07: Modules, Packages, and pip/uv
Learn: import, from...import, pip/uv, if __name__ == "__main__"

In the advanced courses, every file starts with:
    import os
    import json
    from pathlib import Path
    from dotenv import load_dotenv
"""

# --- Importing standard library modules ---
import os
import json
from pathlib import Path

# Use what you imported
current_dir = os.getcwd()
print(f"Current directory: {current_dir}")

# --- from ... import (pick specific things) ---
from datetime import datetime

now = datetime.now()
print(f"Right now: {now.strftime('%Y-%m-%d %H:%M')}")

# --- Import with alias ---
# import pandas as pd      # you'll see this everywhere
# import numpy as np       # standard alias

# --- How Python finds modules ---
# 1. Current directory
# 2. Installed packages (pip/uv)
# 3. Standard library

# --- Installing packages ---
# pip install python-dotenv    # traditional way
# uv add python-dotenv         # modern way (faster)
# uv sync                      # install all from pyproject.toml

# Check what's installed:
# pip list
# uv pip list

# --- if __name__ == "__main__" ---
# This pattern appears in EVERY advanced course file
def main():
    """This runs only when you execute this file directly."""
    print("Running as main script!")
    print("If imported by another file, this won't run.")

# This block runs when: python 07_modules_and_packages.py
# But NOT when: from 07_modules_and_packages import main
if __name__ == "__main__":
    main()
    print("\n✅ Key: __name__ is '__main__' because you ran this file directly")
    print(f"   __name__ = {__name__}")

# 🎯 Exercise: Create a file 'helpers.py' with a function, then import it here