How to automatically format Python and R code in VS Code or Positron

VS Code and Positron include a feature that allows you to take specific actions when saving a file. I have configured VS Code and Positron to automatically format my Python and R code when I save a file. Auto formatting is a great way to ensure your code is consistently formatted correctly.

For formatting Python code, I use ruff (Open VSX, VS Code Marketplace) which has a VS Code extension. For formatting R code, I use air (Open VSX, VS Code Marketplace) which also has a VS Code/Positron extension.

To enable this behviour, add the following to your VS Code configuration file. To open your settings.json file, run one of the following from the Command Palette:

• Run Preferences: Open User Settings (JSON) to modify global user settings.
• Add the following sections:

{
  "[r]": {
    "editor.formatOnSave": true,
    "editor.rulers": [
      80
    ],
    "editor.tabSize": 4
  },
  "[python]": {
    "editor.codeActionsOnSave": {
      "source.organizeImports": "always"
    },
    "editor.defaultFormatter": "charliermarsh.ruff",
    "editor.formatOnSave": true,
    "editor.rulers": [
      80
    ],
    "editor.tabSize": 4
  },
  "ruff.nativeServer": "on",
  "ruff.organizeImports": true
}

Congratulations 🎉 Your code will be automatically formatted whenever you save a Python or R file!