unnecessary-call-around-sorted (C413)

Derived from the flake8-comprehensions linter.

Fix is always available.

What it does

Checks for unnecessary list() or reversed() calls around sorted() calls.

Why is this bad?

It is unnecessary to use list() around sorted(), as the latter already returns a list.

It is also unnecessary to use reversed() around sorted(), as the latter has a reverse argument that can be used in lieu of an additional reversed() call.

In both cases, it's clearer and more efficient to avoid the redundant call.

Examples

reversed(sorted(iterable))

Use instead:

sorted(iterable, reverse=True)

Fix safety

This rule's fix is marked as unsafe, as reversed() and reverse=True will yield different results in the event of custom sort keys or equality functions. Specifically, reversed() will reverse the order of the collection, while sorted() with reverse=True will perform a stable reverse sort, which will preserve the order of elements that compare as equal.