The most common questions and issues users face are aggregated to this FAQ.
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Not yet. Black is fundamentally a command line tool. Many integrations are provided, but a Python interface is not one of them. A simple API is being planned though.
Yes, for the most part. Black is strictly about formatting, nothing else. But because
Black is still in beta, some edges are still a bit rough. To combat
issues, the equivalence of code after formatting is
checked with
limited special cases where the code is allowed to differ. If issues are found, an error
is raised and the file is left untouched. Magical comments that influence linters and
other tools, such as # noqa
, may be moved by Black. See below for more details.
Quite stable. Black aims to enforce one style and one style only, with some room for pragmatism. However, Black is still in beta so style changes are both planned and still proposed on the issue tracker. See The Black Code Style for more details.
Starting in 2022, the formatting output will be stable for the releases made in the same
year (other than unintentional bugs). It is possible to opt-in to the latest formatting
styles, using the --future
flag.
Most likely because it is ignored in .gitignore
or excluded with configuration. See
file collection and discovery
for details.
Black is timid about formatting Jupyter Notebooks. Cells containing any of the following will not be formatted:
-
automagics (e.g.
pip install black
) -
multiline magics, e.g.:
%timeit f(1, \ 2, \ 3)
-
code which
IPython
'sTransformerManager
would transform magics into, e.g.:get_ipython().system('ls')
-
invalid syntax, as it can't be safely distinguished from automagics in the absence of a running
IPython
kernel.
Because they go against PEP 8. E203 falsely triggers on list slices, and adhering to W503 hinders readability because operators are misaligned. Disable W503 and enable the disabled-by-default counterpart W504. E203 should be disabled while changes are still discussed.
Python 2 support has been deprecated since 21.10b0.
This support will be dropped in the first stable release, expected for January 2022.
See [The Black Code Style](the_black_code_style/index.rst) for details.
For formatting, yes! Install with the python2
extra
to format Python 2 files too! In terms of running Black though, Python 3.6 or newer is
required.
Some linters and other tools use magical comments (e.g., # noqa
, # type: ignore
) to
influence their behavior. While Black does its best to recognize such comments and leave
them in the right place, this detection is not and cannot be perfect. Therefore, you'll
sometimes have to manually move these comments to the right place after you format your
codebase with Black.
Yes, there is support for PyPy 3.7 and higher. You cannot format Python 2 files under PyPy, because PyPy's inbuilt ast module does not support this.