module

In Python, a module is a file containing Python code, which can define functions, classes, variables, and more. It can also include runnable code.

Modules allow you to organize your Python code into manageable parts, making it easier to maintain and reuse. Each module has its own namespace, meaning that the variables, functions, and classes defined in a module can be accessed using dot notation, which helps to avoid naming conflicts.

Python provides a rich standard library of modules that you can use to perform a wide variety of tasks, from file I/O to mathematical computations. You can also create your own modules to organize your code. To use a module, you typically import it using the import statement.

Example

Here’s a simple example of creating and using a module in Python. First, create a file named module.py with the following content:

Python module.py 
def greet(name):
    return f"Hello, {name}!"

Now, you can use this module in a Python script:

Python main.py 
import module

message = module.greet("Real Python")
print(message)  # Output: Hello, Real Python!

To use a module from another Python file, you typically import it using an import statement as you did in the code. Once imported, you can use the module’s content in your code.

Step through the example below to watch import module add a single name, module, to the namespace of main.py, while greet stays inside the module’s own namespace:

Interactive diagram — enable JavaScript to view.

The widget opens on the finished run, with Hello, Real Python! under Output. Click Start over, then Next, to replay it. Each step highlights the current line in both files and fills in the main.py namespace and module namespace panels. On step 3, the chips read “found module” in main.py and “found greet” inside the module, which is the lookup that the dot performs.

Now switch Line 3 calls to greet(). Python looks up a bare greet in main.py only, which holds just module, so the chip reads “no greet”, line 3 turns red, and Output shows NameError: name 'greet' is not defined.

Python Modules & Packages

Tutorial

Python Modules and Packages – An Introduction

Explore Python modules and packages, the two mechanisms that make modular programming possible, and learn how imports find your code.

basics python

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By Leodanis Pozo Ramos • Updated Oct. 21, 2026 • Reviewed by Dan Bader
Python Glossary Share Feedback