A tool and pre-commit hook to automatically remove extra calls to keys()
.
pip install unkey
See pre-commit for instructions
Sample .pre-commit-config.yaml
:
- repo: https://github.com/mxr/unkey
rev: v0.0.1
hooks:
- id: unkey
Iterating over a Python dictionary will iterate over its keys, so calls to
keys()
are often not needed. Removing these calls keeps your code terser and
more readable.
unkey
does not support an equivalent of flake8's # noqa
or mypy's #type: ignore
to stop rewriting. Until this feature is available, use an intermediate
variable to prevent rewriting.
# will be rewritten
min({1: 2, 3: 4}.keys()) # becomes min({1: 2, 3: 4})
# will not be rewritten
keys = {1: 2, 3: 4}.keys()
min(keys)
Since AST parsing does not always tell us the type of an object, there may be false positives and undesirable rewrites or bugs. With that said the tool is designed to err on the side of not rewriting rather than being very clever and rewriting as much as possible. To exclude rewrite, see the above section. PRs are always welcome to help out!
Rewrites builtin calls that have iterable arguments
# simple cases
-min({1: 2, 3: 4}.keys())
+min({1: 2, 3: 4})
-min(d.keys())
+min(d)
-min(f().keys())
+min(f())
# more complex cases
-min(d1().x.y(1, 2 ,3, (4, 5)).keys())
+min(d1().x.y(1, 2, 3, (4, 5)))
Rewrites relevant arguments in zip()
-zip(d.keys(), {}.keys(), f().keys(), [1, 2, 3])
+zip(d, {}, f(), [1, 2, 3])
Rewrites relevant arguments in map
and filter
-map(lambda x: x*2, d.keys())
+map(lambda x: x*2, d)
-filter(None, d.keys())
+filteR(None, d)
Rewrites relevant comparisons using in
-if x in d.keys():
+if x in d:
pass
Rewrites relevant list/dict/set comprehensions and generator expressions
-[x for x in d.keys()]
+[x for x in d]
-(x for x in d.keys())
+(x for x in d)
-{x for x in d.keys()}
+{x for x in d}
-{x: x for x in d.keys()}
+{x: x for x in d}
For additional linting in this space check out flake8-comprehensions
.
Rewrites iteration
-for _ in d.keys(): pass
+for _ in d: pass
-for _ in {}.keys(): pass
+for _ in {}: pass
-for _ in f().keys(): pass
+for _ in f(): pass
This tool would not be possible without guidance and tools from Anthony
Sottile, specifically, pyupgrade
and
pre-commit
. unkey
is heavily adapted from the former and code
is attributed wherever possible. Thank you!