In Python, you use the import keyword to make code in one module available in another. Imports in Python are important for structuring your code effectively. Using imports properly will make you more productive, allowing you to reuse code while keeping your projects maintainable.
This tutorial will provide a thorough overview of Python’s import statement and how it works. The import system is powerful, and you’ll learn how to harness this power. While you’ll cover many of the concepts behind Python’s import system, this tutorial is mostly example driven. You’ll learn from several code examples throughout.
In this tutorial, you’ll learn how to:
- Use modules, packages, and namespace packages
- Handle resources and data files inside your packages
- Import modules dynamically at runtime
- Customize Python’s import system
Throughout the tutorial, you’ll see examples of how to play with the Python import machinery in order to work most efficiently. While all the code is shown in the tutorial, you can also download it by clicking the box below:
Get the Source Code: Click here to get the source code you’ll use to learn about the Python import system in this tutorial.
Take the Quiz: Test your knowledge with our interactive “Python import: Advanced Techniques and Tips” quiz. You’ll receive a score upon completion to help you track your learning progress:
Interactive Quiz
Python import: Advanced Techniques and TipsIn this quiz, you'll test your understanding of Python's import statement and how it works. You'll revisit how to use modules and import them dynamically at runtime.
Basic Python import
Python code is organized into both modules and packages. This section will explain how they differ and how you can work with them.
Later in the tutorial, you’ll see some advanced and lesser-known uses of Python’s import system. However, let’s get started with the basics: importing modules and packages.
Modules
The Python.org glossary defines module as follows:
An object that serves as an organizational unit of Python code. Modules have a namespace containing arbitrary Python objects. Modules are loaded into Python by the process of importing. (Source)
In practice, a module usually corresponds to one .py file containing Python code.
The true power of modules is that they can be imported and reused in other code. Consider the following example:
>>> import math
>>> math.pi
3.141592653589793
In the first line, import math, you import the code in the math module and make it available to use. In the second line, you access the pi variable within the math module. math is part of Python’s standard library, which means that it’s always available to import when you’re running Python.
Note that you write math.pi and not just simply pi. In addition to being a module, math acts as a namespace that keeps all the attributes of the module together. Namespaces are useful for keeping your code readable and organized. In the words of Tim Peters:
Namespaces are one honking great idea—let’s do more of those! (Source)
You can list the contents of a namespace with dir():