CSP-P001: Membership Test in List¶

Category: Performance

Severity: MEDIUM

Description¶

Using 'in' with a list literal (or list comprehension) is O(N). Use a set for faster lookups, especially in loops.

Vulnerable Code Example¶

if x in [1, 2, 3, 4]:
    handle(x)

Safer Code Example¶

allowed = {1, 2, 3, 4}
if x in allowed:
    handle(x)

How to Suppress a Finding¶

# ignore
# or
# noqa: CSP-P001