whitespace-before-punctuation (E203)

Derived from the pycodestyle linter.

Fix is always available.

This rule is unstable and in preview. The --preview flag is required for use.

What it does

Checks for the use of extraneous whitespace before ",", ";" or ":".

Why is this bad?

PEP 8 recommends the omission of whitespace in the following cases:

• "Immediately inside parentheses, brackets or braces."
• "Immediately before a comma, semicolon, or colon."

Example

if x == 4: print(x, y); x, y = y , x

Use instead:

if x == 4: print(x, y); x, y = y, x