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https://github.com/MichaelKim0407/flake8-use-fstring
https://github.com/MichaelKim0407/flake8-use-fstring
Last synced: 3 months ago
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- Host: GitHub
- URL: https://github.com/MichaelKim0407/flake8-use-fstring
- Owner: MichaelKim0407
- License: mit
- Created: 2019-08-03T03:04:51.000Z (over 5 years ago)
- Default Branch: develop
- Last Pushed: 2023-11-07T06:55:07.000Z (about 1 year ago)
- Last Synced: 2024-07-09T16:13:37.607Z (4 months ago)
- Language: Python
- Size: 45.9 KB
- Stars: 51
- Watchers: 2
- Forks: 7
- Open Issues: 4
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
- awesome-flake8-extensions - flake8-use-fstring - Report `%`-formatting and `str.format`. (Limitations)
README
# flake8-use-fstring
[](https://github.com/MichaelKim0407/flake8-use-fstring/releases)
[](https://pypi.org/project/flake8-use-fstring)
[](https://pypi.org/project/flake8-use-fstring)
* `master` (release)
[](https://github.com/MichaelKim0407/flake8-use-fstring/tree/master)
[](https://coveralls.io/github/MichaelKim0407/flake8-use-fstring?branch=master)
* `develop` (main)
[](https://github.com/MichaelKim0407/flake8-use-fstring/)
[](https://coveralls.io/github/MichaelKim0407/flake8-use-fstring?branch=develop)
Jump-start into modern Python by forcing yourself to use f-strings.
Works only with `python>=3.6` since it was when f-strings were introduced.
## Installation
```bash
pip install flake8-use-fstring
```
## Reported Errors
* `FS001`: `%` formatting is used.
* `FS002`: `.format` formatting is used.
* `FS003`: f-string missing prefix (ignored by default).
## Available Configurations
### `--percent-greedy` and `--format-greedy`
This plugin checks each python statement (logical line)
and see if `%` or `.format` is used.
Since flake8 is only a code style checker and not a type checker,
it's impossible to tell for sure if the value before `%` or `.format`
is a string.
Thus, greedy level is introduced to control when the plugin should report errors.
* Level 0 (default): only report error if the value before `%` or `.format` is a string literal.
* Level 1: report error if a string literal appears before `%` or `.format` anywhere in the statement.
* Level 2: report any usage of `%` or `.format`.
If the value immediately before `%` or `.format` is not a string,
using level 1 or 2 may result in false positives.
See [tests/example.py](tests/example.py) for examples.
Thus level 0 is the default level.
However, for most projects it should be reasonable to use greedy level 2 with confidence.
To set greedy levels,
set `--percent-greedy=` and `--format-greedy=` in the command line,
or set `percent-greedy=` and `format-greedy=` in the `.flake8` config file.
### `--enable-extensions=FS003` and `--fstring-ignore-format`
This plugin can also check for strings that appear to be f-strings but don't have the `f` prefix.
`FS003` will be reported if a string:
* is not prefixed with `f`
* contains at least one pair of `{}`
* is not prefixed with `r` (because r-strings are often regexes that would contain `{}`)
Due to the potential for false positives, this check (`FS003`) is disabled by default.
To enable this check,
add the `--enable-extensions=FS003` command line option,
or set `enable-extensions=FS003` in the `.flake8` config file.
**NOTE**:
If you use the `--ignore` option of `flake8`, the default ignore list will be overwritten.
See [`--ignore`](https://flake8.pycqa.org/en/latest/user/options.html#cmdoption-flake8-ignore)
vs [`--extend-ignore`](https://flake8.pycqa.org/en/latest/user/options.html#cmdoption-flake8-extend-ignore).
The missing prefix check normally ignores strings that are using `%` or `.format` formatting.
To check those strings as well,
add the `--fstring-ignore-format` command line option,
or set `fstring-ignore-format=True` in the `.flake8` config file.
## Additional Notes
### Byte literals
Byte literals (strings that are prefixed with a literal `b`) will not be checked since Python does not support f-strings for them (as of 3.9).