unary-prefix-increment-decrement (B002)

Derived from the flake8-bugbear linter.

What it does

Checks for the attempted use of the unary prefix increment (++) or decrement operator (--).

Why is this bad?

Python does not support the unary prefix increment or decrement operator. Writing ++n is equivalent to +(+(n)) and writing --n is equivalent to -(-(n)). In both cases, it is equivalent to n.

Example

++x
--y

Use instead:

x += 1
y -= 1

References

• Python documentation: Unary arithmetic and bitwise operations
• Python documentation: Augmented assignment statements