๐Ÿงน Using Flake8, An Introduction - โ€œA tool for cleaning your Python codeโ€ยถ

  • Tags: [โ€Beginnerโ€]
  • Categories: [โ€Pythonโ€]
  • Date: โ€œ2020-09-29โ€

Introductionยถ

Flake8 is one of the more popular linting tools. This post tells what it is, how to set it up, and how to get started using it.

The Difference Between What Happens When The Python Interpreter Catches Errors And What Happens When You Run A Linterยถ

When you use the Python interpreter to run a Python program, it may not run your program because it catches errors that Python cannot understand. The kinds of errors that keep your Python file from running are called Syntax errors. Once you remove the syntax errors from your program, the Python interpreter runs it, and it begins to do its processing. If it has errors that prevent it from running correctly, these are called run-time errors.

Linting tools inspect your Python files for both kinds of errors plus coding conventions accepted by the Python community. Using a linting tool makes it easier for both the Python interpreter to run your programs and for anyone who works on projects with you to read your code, since they help you follow agreed upon standards.

How Flake8 Helps Furtherยถ

Flake8 looks for code that does not follow accepted Python practices according to PEP8.

Flake8 Environmentยถ

You can run Flake8 from the command line or from an editor, such as PyCharm or Visual Studio Code. It works on Linux, Windows, and Mac. You can also integrate it with your GitHub projects. We will concentrate on using it from the command line, since using it from an editor uses its command line options. You can experiment with its configurations and easily see more directly how they affect how it runs.

Installing Flake8ยถ

You would want to install Flake8 into your default Python environment, since you would want to check all of your Python code with it, but you can also install it for every version of Python you have on your system. Assuming that you have Python installed, to install into your default environment, from the command line, type:

pip install flake8

To install Flake8 for a particular version of Python, type:

python<version> -m pip install flake8

Where <version> is any version of Python on your system.

Running Flake8ยถ

To run Flake8, type:

Flake8

This starts Flake8.

You can run it against a version other than the default. For example:

python2.7 -m flake8

Where python2.7 is one version of Python, and -m runs Flake8 as a standalone module.

You can also run Flake8 against individual Python files and entire directories. To do that, add the name of the Python file or folder to the command line.

Finally, you can run Flake8 using any of its command line options, and it has a very comprehensive configuration scheme that uses configuration files.

Getting Helpยถ

To get help with Flake8, type:

flake8 --help

About The Authorยถ

Jim Homme is a former professional musician, father of three, husband, and a 32-year veteran in Information Technology. He loves to read and play chess. He leads a team of accessibility testers at Bender Consulting Services. He is the owner of jimhomme.com, where he writes about Python and related technologies.