Modules and Packages

Importing standard library modules, creating your own modules, and using pip.

What is a Module?

A module is simply a .py file containing Python definitions and statements. Python ships with a huge standard library of ready-to-use modules.

Importing Modules

import math
print(math.pi)          # 3.141592653589793
print(math.sqrt(144))  # 12.0

from math import factorial, gcd
print(factorial(5))    # 120
print(gcd(48, 18))     # 6

Creating Your Own Module

Create a file mytools.py in the same folder:

# mytools.py
def celsius_to_fahrenheit(c):
    return c * 9 / 5 + 32

PI = 3.14159

Then import it:

import mytools
print(mytools.celsius_to_fahrenheit(100))  # 212.0

Installing Third-Party Packages with pip

In the Visual Studio 2026 Terminal (View → Terminal):

pip install requests
pip install pandas
pip install matplotlib
pip list          # show installed packages