Modules and Imports in Python

When you write Python programs, you don’t have to reinvent the wheel every time. Python provides a way to organize and reuse code using modules.

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📝 If You Want to Practice the Code

If you plan to practice the Python code mentioned within this blog post, you’ll need a working Python environment. You can execute the commands in one of the following ways (choose only one option):

• From a Python prompt in your terminal or command line – see Getting Started with Python and Virtual Environment in Python and How to Set One Up
• Using Miniconda and Jupyter Notebook – see How to Install and Set Up Miniconda and Install Jupytor Notebook Windows, How to Install and Set Up Miniconda on MacOS, How to Install and Set Up Miniconda on Linux (Ubuntu), and Getting Started with Jupyter Notebooks.
• On Google Colab (browser-based, no installation required) – see Getting Started with Google Colab.
• Through VS Code – see Setting Up VS Code for Python Development.

👉 Choose whichever environment you’re most comfortable with. If you haven’t set up Python yet, start with one of the installation posts before trying the examples here.

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What is a Module?

A module is just a Python file that contains code — functions, classes, or variables — that you can reuse in other programs.

• If you create a file called math_tools.py with a function inside, that’s a module.
• Python also comes with a big set of built-in modules (like math, os, and datetime).
• You can also install extra modules (called packages) with tools like pip.

Example:

# math_tools.py
def add(a, b):
    return a + b

Here, math_tools.py is a module that defines one function.

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Importing a Module

To use code from another module, you use the import statement.

Import the whole module

import math

print(math.sqrt(16))  # Output: 4.0

Import a specific function or class

from math import sqrt

print(sqrt(25))  # Output: 5.0

Give a module an alias (nickname)

import math as m

print(m.pi)  # Output: 3.141592653589793

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Your Own Modules

If you have math_tools.py in the same folder as your main program, you can import it:

import math_tools

result = math_tools.add(3, 4)
print(result)  # Output: 7

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Why Are Imports Useful?

• They keep code organized and split into logical pieces.
• They allow you to reuse code instead of copying it everywhere.
• They give access to Python’s standard library and third-party libraries like requests, numpy, or the Azure SDKs.

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Quick Recap

• A module is just a Python file with reusable code.
• Use import to bring in a module.
• You can import everything, just what you need, or rename it with an alias.

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👉 Next Step: Try creating your own small module with a function or two, then import it into another Python file. That’s the best way to understand how modules and imports work.