yapf

YAPF Introduction YAPF is a Python formatter based on clang-format (developed by Daniel Jasper). In essence, the algorithm takes the code and calculates the best formatting that conforms to the configured style. It takes away a lot of the drudgery of maintaining your code. The ultimate goal is that the code YAPF produces is as good as the code that a programmer would write if they were following the style guide. Note YAPF is not an official Google product (experimental or otherwise), it is just code that happens to be owned by Google. Installation To install YAPF from PyPI: $ pip install yapf YAPF is still considered in "beta" stage, and the released version may change often; therefore, the best way to keep up-to-date with the latest development is to clone this repository or install directly from github: $ pip install git+https://github.com/google/yapf.git Note that if you intend to use YAPF as a command-line tool rather than as a library, installation is not necessary. YAPF supports being run as a directory by the Python interpreter. If you cloned/unzipped YAPF into DIR, it's possible to run: $ PYTHONPATH=DIR python DIR/yapf [options] ... Using YAPF within your favorite editor YAPF is supported by multiple editors via community extensions or plugins. See Editor Support for more info. Required Python versions YAPF supports Python 3.7+. Usage usage: yapf [-h] [-v] [-d | -i | -q] [-r | -l START-END] [-e PATTERN] [--style STYLE] [--style-help] [--no-local-style] [-p] [-m] [-vv] [files ...] Formatter for Python code. positional arguments: files reads from stdin when no files are specified. optional arguments: -h, --help show this help message and exit -v, --version show program's version number and exit -d, --diff print the diff for the fixed source -i, --in-place make changes to files in place -q, --quiet output nothing and set return value -r, --recursive run recursively over directories -l START-END, --lines START-END range of lines to reformat, one-based -e PATTERN, --exclude PATTERN patterns for files to exclude from formatting --style STYLE specify formatting style: either a style name (for example "pep8" or "google"), or the name of a file with style settings. The default is pep8 unless a .style.yapf or setup.cfg or pyproject.toml file located in the same directory as the source or one of its parent directories (for stdin, the current directory is used). --style-help show style settings and exit; this output can be saved to .style.yapf to make your settings permanent --no-local-style don't search for local style definition -p, --parallel run YAPF in parallel when formatting multiple files. -m, --print-modified print out file names of modified files -vv, --verbose print out file names while processing Return Codes Normally YAPF returns zero on successful program termination and non-zero otherwise. If --diff is supplied, YAPF returns zero when no changes were necessary, non-zero otherwise (including program error). You can use this in a CI workflow to test that code has been YAPF-formatted. Excluding files from formatting (.yapfignore or pyproject.toml) In addition to exclude patterns provided on commandline, YAPF looks for additional patterns specified in a file named .yapfignore or pyproject.toml located in the working directory from which YAPF is invoked. .yapfignore's syntax is similar to UNIX's filename pattern matching: * matches everything ? matches any single character [seq] matches any character in seq [!seq] matches any character not in seq Note that no entry should begin with ./. If you use pyproject.toml, exclude patterns are specified by ignore_patterns key in [tool.yapfignore] section. For example: [tool.yapfignore] ignore_patterns = [ "temp/**/*.py", "temp2/*.py" ] Formatting style The formatting style used by YAPF is configurable and there are many "knobs" that can be used to tune how YAPF does formatting. See the style.py module for the full list. To control the style, run YAPF with the --style argument. It accepts one of the predefined styles (e.g., pep8 or google), a path to a configuration file that specifies the desired style, or a dictionary of key/value pairs. The config file is a simple listing of (case-insensitive) key = value pairs with a [style] heading. For example: [style] based_on_style = pep8 spaces_before_comment = 4 split_before_logical_operator = true The based_on_style setting determines which of the predefined styles this custom style is based on (think of it like subclassing). Four styles are predefined: pep8 (default) google (based off of the Google Python Style Guide) yapf (for use with Google open source projects) facebook See _STYLE_NAME_TO_FACTORY in style.py for details. It's also possible to do the same on the command line with a dictionary. For example: --style='{based_on_style: pep8, indent_width: 2}' This will take the pep8 base style and modify it to have two space indentations. YAPF will search for the formatting style in the following manner: Specified on the command line In the [style] section of a .style.yapf file in either the current directory or one of its parent directories. In the [yapf] section of a setup.cfg file in either the current directory or one of its parent directories. In the [tool.yapf] section of a pyproject.toml file in either the current directory or one of its parent directories. In the [style] section of a ~/.config/yapf/style file in your home directory. If none of those files are found, the default style PEP8 is used. Example An example of the type of formatting that YAPF can do, it will take this ugly code: