flake8-comprehensions 1.1.0

A flake8 plugin to help you write better list/set/dict comprehensions.

Flake8 Comprehensions

A flake8 plugin that helps you write better list/set/dict comprehensions.

• Free software: ISC license

Installation

Install from pip with:

pip install flake8-comprehensions

It will then automatically be run as part of flake8; you can check it has been picked up with:

$ flake8 --version
2.4.1 (pep8: 1.7.0, pyflakes: 0.8.1, flake8-comprehensions: 1.0.0, mccabe: 0.3.1) CPython 2.7.11 on Darwin

Rules

C400: Unnecessary generator

Complains about unnecessary use of a generator inside a call to list()/set()/dict() when an equivalent comprehension would do. For example:

• list(f(x) for x in foo) -> [f(x) for x in foo]

• set(f(x) for x in foo) -> {f(x) for x in foo}

• dict((x, f(x)) for x in foo) -> {x: f(x) for x in foo}

This rule triggers a message like:

$ flake8 file.py
file.py:1:1: C400 Unnecessary generator - rewrite as a list comprehension.

C401: Unnecessary list comprehension

Complains about unnecessary use of a list comprehension, for example when inside a set() call. For example:

• set([f(x) for x in foo]) -> {f(x) for x in foo}

• dict([(x, f(x)) for x in foo]) -> {x: f(x) for x in foo}

This triggers a message like:

$ flake8 file.py
file.py:1:1: C401 Unnecessary list comprehension - rewrite as a set comprehension.

C402: Unnecessary list literal

Complains about unnecessary list literals, for example when inside a set() call. For example:

• set([1, 2]) -> {1, 2}

• set([]) -> set()

• dict([]) -> {}

• dict([(1, 2)]) -> {1: 2}

This triggers a message like:

$ flake8 file.py
file.py:1:1: C402 Unnecessary list literal - rewrite as a set literal.

History

Pending Release

• New release notes here

1.1.0 (2016-04-06)

• C401 rule that complains about unnecessary list comprehensions inside calls to set() or dict().

• C402 rule that complains about unnecessary list literals inside calls to set() or dict().

1.0.0 (2016-04-05)

• C400 rule that complains about an unnecessary usage of a generator when a list/set/dict comprehension would do.