Imports & Modules in Python
From the Python cheat sheet · Modules & Virtual Environments · verified Jul 2026
Imports & Modules
Import standard library and custom modules; structure runnable scripts.
python
import os
from pathlib import Path
from datetime import datetime, timedelta
from collections import defaultdict, Counter
import json
# Alias
import numpy as np
# Import specific names
from math import sqrt, pi
# Script entry point — only runs when invoked directly,
# not when the module is imported
def main():
print("Running as a script")
if __name__ == "__main__":
main()💡 A module is just a .py file — a package is a directory with __init__.py
⚡ Always wrap script entry logic in if __name__ == "__main__": so imports stay clean
📌 Avoid "from x import *" in production — it makes it unclear where names come from
🟢 Use relative imports (from . import) inside packages, absolute imports elsewhere
importsmodulespackages