duplicate-value (B033)

Added in v0.0.271 · Related issues · View source

Derived from the flake8-bugbear linter.

Fix is sometimes available.

What it does

Checks for set literals that contain duplicate items.

Why is this bad?

In Python, sets are unordered collections of unique elements. Including a duplicate item in a set literal is redundant, as the duplicate item will be replaced with a single item at runtime.

Example

{1, 2, 3, 1}

Use instead:

{1, 2, 3}

Fix Safety

This rule's fix is marked as unsafe if the replacement would remove comments attached to the original expression, potentially losing important context or documentation.

For example:

{
    1,
    2,
    # Comment
    1,
}