use-implicit-booleaness-not-len / C1802#

Message emitted:

Do not use len(SEQUENCE) without comparison to determine if a sequence is empty

Description:

Used when Pylint detects that len(sequence) is being used without explicit comparison inside a condition to determine if a sequence is empty. Instead of coercing the length to a boolean, either rely on the fact that empty sequences are false or compare the length against a scalar.

Correct code:

fruits = ["orange", "apple"]

if fruits:
    print(fruits)

Problematic code:

fruits = ["orange", "apple"]

if len(fruits):  # [use-implicit-booleaness-not-len]
    print(fruits)

Created by the refactoring checker.