ruff

An extremely fast Python linter and code formatter, written in Rust.

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Quick Overview

Ruff is a fast, powerful, and extensible Python linter that helps developers write cleaner, more consistent, and more maintainable code. It is designed to be highly configurable and integrates seamlessly with popular code editors and development tools.

Pros

Fast and Efficient: Ruff is built on top of the Rust programming language, making it significantly faster than traditional Python linters.
Highly Configurable: Ruff offers a wide range of configuration options, allowing developers to customize the linting rules to fit their specific needs.
Extensible: Ruff supports a wide range of plugins and custom rules, making it easy to extend its functionality.
Integrates Seamlessly: Ruff integrates with popular code editors and development tools, such as Visual Studio Code, PyCharm, and Sublime Text.

Cons

Learning Curve: Ruff's extensive configuration options and plugin system may have a steeper learning curve for some developers.
Dependency on Rust: Ruff's reliance on the Rust programming language may be a drawback for developers who are not familiar with Rust.
Limited Community: Compared to more established Python linters, Ruff has a smaller community and may have fewer resources available.
Potential Compatibility Issues: As a relatively new tool, Ruff may have some compatibility issues with certain Python packages or development environments.

Code Examples

# Example 1: Checking for unused imports
import os
import sys
import math

# This import is unused
import random

# Example 2: Enforcing PEP8 style guidelines
def my_function(a, b):
    c = a + b
    d = c * 2
    return d

# Example 3: Detecting type hints
def add_numbers(a: int, b: int) -> int:
    return a + b

# Example 4: Checking for unnecessary variable assignments
x = 5
y = 10
z = x + y

Getting Started

To get started with Ruff, follow these steps:

Install Ruff using pip:

pip install ruff

Run Ruff on your Python project:

ruff check .

This will run the linter on all Python files in the current directory and its subdirectories.

Customize the Ruff configuration:

Create a .ruff.toml file in the root of your project and add your desired configuration options. For example:

select = ["E", "F", "W", "I"]
ignore = ["E501"]

This configuration will enable the E, F, W, and I error codes, but ignore the E501 (line too long) error.

Integrate Ruff with your code editor:

Ruff supports integration with various code editors, such as Visual Studio Code, PyCharm, and Sublime Text. Follow the instructions in the Ruff documentation to set up the integration for your preferred editor.

That's it! With these steps, you can start using Ruff to improve the quality and consistency of your Python code.

Competitor Comparisons

black

38,528

The uncompromising Python code formatter

Pros of Black

Widely adopted and considered the standard Python code formatter
Deterministic output, ensuring consistent formatting across different environments
Integrates well with popular IDEs and CI/CD pipelines

Cons of Black

Limited configurability, enforcing a strict style that may not suit all projects
Slower performance compared to Ruff, especially on larger codebases
Focuses solely on code formatting, lacking additional linting capabilities

Code Comparison

Black formatting:

def long_function_name(
    var_one: int, var_two: str, var_three: float, var_four: bool
) -> None:
    print(f"{var_one}, {var_two}, {var_three}, {var_four}")

Ruff formatting:

def long_function_name(
    var_one: int,
    var_two: str,
    var_three: float,
    var_four: bool,
) -> None:
    print(f"{var_one}, {var_two}, {var_three}, {var_four}")

Key Differences

Ruff is significantly faster than Black, offering improved performance for large projects
Ruff provides both formatting and linting capabilities, while Black focuses solely on formatting
Ruff offers more configuration options, allowing for greater customization of code style
Black has a larger user base and ecosystem support, being the de facto standard for Python formatting

flake8

3,391

flake8 is a python tool that glues together pycodestyle, pyflakes, mccabe, and third-party plugins to check the style and quality of some python code.

Pros of Flake8

Established and widely adopted in the Python community
Extensive plugin ecosystem for customization
Supports a broad range of Python versions

Cons of Flake8

Slower performance compared to Ruff
Requires separate installation of plugins
Limited auto-fix capabilities

Code Comparison

Flake8:

import subprocess

def run_command(cmd):
    result = subprocess.run(cmd, shell=True, capture_output=True, text=True)
    return result.stdout.strip()

Ruff:

import subprocess

def run_command(cmd: str) -> str:
    result = subprocess.run(cmd, shell=True, capture_output=True, text=True)
    return result.stdout.strip()

Ruff provides type annotations and enforces them by default, while Flake8 requires additional configuration or plugins for type checking. Ruff also includes more comprehensive linting rules out of the box, whereas Flake8 often requires additional plugins for similar functionality.

Both tools aim to improve code quality, but Ruff offers faster performance and more features in a single package. Flake8, however, benefits from its long-standing presence in the Python ecosystem and extensive community support.

pylint

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Pros of Pylint

More established and mature project with a longer history
Offers a wider range of checks and features beyond just linting
Highly configurable with extensive documentation

Cons of Pylint

Slower performance, especially on larger codebases
Can be overly verbose and produce false positives
Steeper learning curve for configuration and customization

Code Comparison

Pylint configuration example:

[MASTER]
ignore=CVS
ignore-patterns=
persistent=yes
load-plugins=
jobs=1
unsafe-load-any-extension=no
extension-pkg-whitelist=

Ruff configuration example:

[tool.ruff]
line-length = 88
select = ["E", "F", "I"]
ignore = ["E501"]

Ruff is designed to be faster and more user-friendly, with a simpler configuration process. It focuses primarily on linting and formatting, while Pylint offers a broader range of code analysis features. Ruff's performance advantage is particularly noticeable in larger projects, but it may not cover all the checks that Pylint provides. The choice between the two often depends on specific project requirements and team preferences.

yapf

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A formatter for Python files

Pros of YAPF

Highly configurable with many style options
Supports multiple Python versions (2.7 and 3.6+)
Can be used as a library for integration into other tools

Cons of YAPF

Slower performance compared to Ruff
Less frequent updates and maintenance
Limited to code formatting, lacking additional linting features

Code Comparison

YAPF:

def long_function_name(
    var_one, var_two, var_three,
    var_four):
    print(var_one)

Ruff:

def long_function_name(
    var_one,
    var_two,
    var_three,
    var_four,
):
    print(var_one)

Key Differences

Ruff is significantly faster, often 10-100x quicker than YAPF
Ruff combines linting and formatting, while YAPF focuses solely on formatting
Ruff is written in Rust, offering better performance and memory efficiency
YAPF provides more granular control over formatting styles
Ruff has a more active development community and frequent updates

Both tools aim to improve Python code quality, but Ruff offers a more comprehensive solution with its combined linting and formatting capabilities, along with superior performance. YAPF, however, may be preferred by those who require highly specific formatting control or need to support older Python versions.

autopep8

4,558

A tool that automatically formats Python code to conform to the PEP 8 style guide.

Pros of autopep8

Established and widely used in the Python community
Focuses specifically on PEP 8 compliance
Integrates well with various editors and CI/CD pipelines

Cons of autopep8

Slower performance compared to Ruff
Limited scope, primarily addressing PEP 8 style issues
Less frequent updates and maintenance

Code Comparison

autopep8:

import autopep8

code = """
def foo  (x) :
    print( x)
"""
fixed_code = autopep8.fix_code(code)
print(fixed_code)

Ruff:

from ruff import fix

code = """
def foo  (x) :
    print( x)
"""
fixed_code = fix(code)
print(fixed_code)

Key Differences

Ruff is written in Rust, offering significantly faster performance
Ruff provides a broader range of linting and fixing capabilities beyond PEP 8
autopep8 is more focused on PEP 8 compliance and has a longer history in the Python ecosystem
Ruff is actively developed with frequent updates and new features
autopep8 has better integration with existing tools due to its established presence

wemake-python-styleguide

2,493

The strictest and most opinionated python linter ever!

Pros of wemake-python-styleguide

More comprehensive and stricter set of rules, enforcing a highly opinionated coding style
Focuses on maintaining a consistent and clean codebase across large projects
Includes advanced static analysis features beyond basic linting

Cons of wemake-python-styleguide

Slower performance compared to Ruff, especially on larger codebases
Less flexibility in rule customization, which may be too restrictive for some projects
Steeper learning curve due to its extensive ruleset and strict defaults

Code Comparison

wemake-python-styleguide:

from typing import List

def process_items(items: List[str]) -> List[str]:
    return [item.strip().lower() for item in items if item]

Ruff:

def process_items(items):
    return [item.strip().lower() for item in items if item]

The wemake-python-styleguide example enforces type annotations, while Ruff allows for more flexible code style by default. However, Ruff can be configured to enforce similar rules if desired, offering a balance between strictness and performance.

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README

Ruff

Docs | Playground

An extremely fast Python linter and code formatter, written in Rust.

Shows a bar chart with benchmark results.

Linting the CPython codebase from scratch.

â¡ï¸ 10-100x faster than existing linters (like Flake8) and formatters (like Black)
ð Installable via pip
ð ï¸ pyproject.toml support
ð¤ Python 3.13 compatibility
âï¸ Drop-in parity with Flake8, isort, and Black
ð¦ Built-in caching, to avoid re-analyzing unchanged files
ð§ Fix support, for automatic error correction (e.g., automatically remove unused imports)
ð Over 800 built-in rules, with native re-implementations of popular Flake8 plugins, like flake8-bugbear
â¨ï¸ First-party editor integrations for VS Code and more
ð Monorepo-friendly, with hierarchical and cascading configuration

Ruff aims to be orders of magnitude faster than alternative tools while integrating more functionality behind a single, common interface.

Ruff can be used to replace Flake8 (plus dozens of plugins), Black, isort, pydocstyle, pyupgrade, autoflake, and more, all while executing tens or hundreds of times faster than any individual tool.

Ruff is extremely actively developed and used in major open-source projects like:

...and many more.

Ruff is backed by Astral. Read the launch post, or the original project announcement.

Testimonials

SebastiÃ¡n RamÃrez, creator of FastAPI:

Ruff is so fast that sometimes I add an intentional bug in the code just to confirm it's actually running and checking the code.

Nick Schrock, founder of Elementl, co-creator of GraphQL:

Why is Ruff a gamechanger? Primarily because it is nearly 1000x faster. Literally. Not a typo. On our largest module (dagster itself, 250k LOC) pylint takes about 2.5 minutes, parallelized across 4 cores on my M1. Running ruff against our entire codebase takes .4 seconds.

Bryan Van de Ven, co-creator of Bokeh, original author of Conda:

Ruff is ~150-200x faster than flake8 on my machine, scanning the whole repo takes ~0.2s instead of ~20s. This is an enormous quality of life improvement for local dev. It's fast enough that I added it as an actual commit hook, which is terrific.

Timothy Crosley, creator of isort:

Just switched my first project to Ruff. Only one downside so far: it's so fast I couldn't believe it was working till I intentionally introduced some errors.

Tim Abbott, lead developer of Zulip:

This is just ridiculously fast... ruff is amazing.

For more, see the documentation.

Getting Started
Configuration
Rules
Contributing
Support
Acknowledgements
Who's Using Ruff?
License

Getting Started

For more, see the documentation.

Installation

Ruff is available as ruff on PyPI:

# With pip.
pip install ruff

# With pipx.
pipx install ruff

Starting with version 0.5.0, Ruff can be installed with our standalone installers:

# On macOS and Linux.
curl -LsSf https://astral.sh/ruff/install.sh | sh

# On Windows.
powershell -c "irm https://astral.sh/ruff/install.ps1 | iex"

# For a specific version.
curl -LsSf https://astral.sh/ruff/0.6.4/install.sh | sh
powershell -c "irm https://astral.sh/ruff/0.6.4/install.ps1 | iex"

You can also install Ruff via Homebrew, Conda, and with a variety of other package managers.

Usage

To run Ruff as a linter, try any of the following:

ruff check                          # Lint all files in the current directory (and any subdirectories).
ruff check path/to/code/            # Lint all files in `/path/to/code` (and any subdirectories).
ruff check path/to/code/*.py        # Lint all `.py` files in `/path/to/code`.
ruff check path/to/code/to/file.py  # Lint `file.py`.
ruff check @arguments.txt           # Lint using an input file, treating its contents as newline-delimited command-line arguments.

Or, to run Ruff as a formatter:

ruff format                          # Format all files in the current directory (and any subdirectories).
ruff format path/to/code/            # Format all files in `/path/to/code` (and any subdirectories).
ruff format path/to/code/*.py        # Format all `.py` files in `/path/to/code`.
ruff format path/to/code/to/file.py  # Format `file.py`.
ruff format @arguments.txt           # Format using an input file, treating its contents as newline-delimited command-line arguments.

Ruff can also be used as a pre-commit hook via ruff-pre-commit:

- repo: https://github.com/astral-sh/ruff-pre-commit
  # Ruff version.
  rev: v0.6.4
  hooks:
    # Run the linter.
    - id: ruff
      args: [ --fix ]
    # Run the formatter.
    - id: ruff-format

Ruff can also be used as a VS Code extension or with various other editors.

Ruff can also be used as a GitHub Action via ruff-action:

name: Ruff
on: [ push, pull_request ]
jobs:
  ruff:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: chartboost/ruff-action@v1

Configuration

Ruff can be configured through a pyproject.toml, ruff.toml, or .ruff.toml file (see: Configuration, or Settings for a complete list of all configuration options).

If left unspecified, Ruff's default configuration is equivalent to the following ruff.toml file:

# Exclude a variety of commonly ignored directories.
exclude = [
    ".bzr",
    ".direnv",
    ".eggs",
    ".git",
    ".git-rewrite",
    ".hg",
    ".ipynb_checkpoints",
    ".mypy_cache",
    ".nox",
    ".pants.d",
    ".pyenv",
    ".pytest_cache",
    ".pytype",
    ".ruff_cache",
    ".svn",
    ".tox",
    ".venv",
    ".vscode",
    "__pypackages__",
    "_build",
    "buck-out",
    "build",
    "dist",
    "node_modules",
    "site-packages",
    "venv",
]

# Same as Black.
line-length = 88
indent-width = 4

# Assume Python 3.8
target-version = "py38"

[lint]
# Enable Pyflakes (`F`) and a subset of the pycodestyle (`E`)  codes by default.
select = ["E4", "E7", "E9", "F"]
ignore = []

# Allow fix for all enabled rules (when `--fix`) is provided.
fixable = ["ALL"]
unfixable = []

# Allow unused variables when underscore-prefixed.
dummy-variable-rgx = "^(_+|(_+[a-zA-Z0-9_]*[a-zA-Z0-9]+?))$"

[format]
# Like Black, use double quotes for strings.
quote-style = "double"

# Like Black, indent with spaces, rather than tabs.
indent-style = "space"

# Like Black, respect magic trailing commas.
skip-magic-trailing-comma = false

# Like Black, automatically detect the appropriate line ending.
line-ending = "auto"

Note that, in a pyproject.toml, each section header should be prefixed with tool.ruff. For example, [lint] should be replaced with [tool.ruff.lint].

Some configuration options can be provided via dedicated command-line arguments, such as those related to rule enablement and disablement, file discovery, and logging level:

ruff check --select F401 --select F403 --quiet

The remaining configuration options can be provided through a catch-all --config argument:

ruff check --config "lint.per-file-ignores = {'some_file.py' = ['F841']}"

To opt in to the latest lint rules, formatter style changes, interface updates, and more, enable preview mode by setting preview = true in your configuration file or passing --preview on the command line. Preview mode enables a collection of unstable features that may change prior to stabilization.

See ruff help for more on Ruff's top-level commands, or ruff help check and ruff help format for more on the linting and formatting commands, respectively.

Rules

Ruff supports over 800 lint rules, many of which are inspired by popular tools like Flake8, isort, pyupgrade, and others. Regardless of the rule's origin, Ruff re-implements every rule in Rust as a first-party feature.

By default, Ruff enables Flake8's F rules, along with a subset of the E rules, omitting any stylistic rules that overlap with the use of a formatter, like ruff format or Black.

If you're just getting started with Ruff, the default rule set is a great place to start: it catches a wide variety of common errors (like unused imports) with zero configuration.

Beyond the defaults, Ruff re-implements some of the most popular Flake8 plugins and related code quality tools, including:

For a complete enumeration of the supported rules, see Rules.

Contributing

Contributions are welcome and highly appreciated. To get started, check out the contributing guidelines.

You can also join us on Discord.

Support

Having trouble? Check out the existing issues on GitHub, or feel free to open a new one.

You can also ask for help on Discord.

Acknowledgements

Ruff's linter draws on both the APIs and implementation details of many other tools in the Python ecosystem, especially Flake8, Pyflakes, pycodestyle, pydocstyle, pyupgrade, and isort.

In some cases, Ruff includes a "direct" Rust port of the corresponding tool. We're grateful to the maintainers of these tools for their work, and for all the value they've provided to the Python community.

Ruff's formatter is built on a fork of Rome's rome_formatter, and again draws on both API and implementation details from Rome, Prettier, and Black.

Ruff's import resolver is based on the import resolution algorithm from Pyright.

Ruff is also influenced by a number of tools outside the Python ecosystem, like Clippy and ESLint.

Ruff is the beneficiary of a large number of contributors.

Ruff is released under the MIT license.

Who's Using Ruff?

Ruff is used by a number of major open-source projects and companies, including:

Albumentations
Amazon (AWS SAM)
Anthropic (Python SDK)
Apache Airflow
AstraZeneca (Magnus)
Babel
Benchling (Refac)
Bokeh
Cryptography (PyCA)
CERN (Indico)
DVC
Dagger
Dagster
Databricks (MLflow)
Dify
FastAPI
Godot
Gradio
Great Expectations
HTTPX
Hatch
Home Assistant
Hugging Face (Transformers, Datasets, Diffusers)
IBM (Qiskit)
ING Bank (popmon, probatus)
Ibis
ivy
Jupyter
Kraken Tech
LangChain
Litestar
LlamaIndex
Matrix (Synapse)
MegaLinter
Meltano (Meltano CLI, Singer SDK)
Microsoft (Semantic Kernel, ONNX Runtime, LightGBM)
Modern Treasury (Python SDK)
Mozilla (Firefox)
Mypy
Nautobot
Netflix (Dispatch)
Neon
Nokia
NoneBot
NumPyro
ONNX
OpenBB
Open Wine Components
PDM
PaddlePaddle
Pandas
Pillow
Poetry
Polars
PostHog
Prefect (Python SDK, Marvin)
PyInstaller
PyMC
PyMC-Marketing
pytest
PyTorch
Pydantic
Pylint
PyVista
Reflex
River
Rippling
Robyn
Saleor
Scale AI (Launch SDK)
SciPy
Snowflake (SnowCLI)
Sphinx
Stable Baselines3
Starlette
Streamlit
The Algorithms
Vega-Altair
WordPress (Openverse)
ZenML
Zulip
build (PyPA)
cibuildwheel (PyPA)
delta-rs
featuretools
meson-python
nox
pip

Show Your Support

If you're using Ruff, consider adding the Ruff badge to your project's README.md:

[![Ruff](https://img.shields.io/endpoint?url=https://raw.githubusercontent.com/astral-sh/ruff/main/assets/badge/v2.json)](https://github.com/astral-sh/ruff)

...or README.rst:

.. image:: https://img.shields.io/endpoint?url=https://raw.githubusercontent.com/astral-sh/ruff/main/assets/badge/v2.json
    :target: https://github.com/astral-sh/ruff
    :alt: Ruff

...or, as HTML:

<a href="https://github.com/astral-sh/ruff"><img src="https://img.shields.io/endpoint?url=https://raw.githubusercontent.com/astral-sh/ruff/main/assets/badge/v2.json" alt="Ruff" style="max-width:100%;"></a>

License

This repository is licensed under the MIT License

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Quick Overview

Pros

Cons

Code Examples

Getting Started

Competitor Comparisons

Pros of Black

Cons of Black

Code Comparison

Key Differences

Pros of Flake8

Cons of Flake8

Code Comparison

Pros of Pylint

Cons of Pylint

Code Comparison

Pros of YAPF

Cons of YAPF

Code Comparison

Key Differences

Pros of autopep8

Cons of autopep8

Code Comparison

Key Differences

Pros of wemake-python-styleguide

Cons of wemake-python-styleguide

Code Comparison

Convert designs to code with AI

README

Ruff

Testimonials

Table of Contents

Getting Started

Installation

Usage

Configuration

Rules

Contributing

Support

Acknowledgements

Who's Using Ruff?

Show Your Support

License

Top Related Projects

Convert designs to code with AI