PY3.W0631

Undefined loop variable

Used when a loop variable (i.e. defined by a for loop or a list comprehension or a generator expression) is used outside the loop.

Noncompliant Code:

Copy
data = {'x': 1, 'y': 2, 'z': 3}
for k, v in data.items():
    x = f'key: {k} => value: {v}'
    break

print(x)

Compliant Code:

Copy
data = {'x': 1, 'y': 2, 'z': 3}
x = None
for k, v in data.items():
    x = f'key: {k} => value: {v}'
    break

print(x)

The content on this page is adapted from the Pylint User Guide, Copyright ©2003-2022, Logilab, PyCQA and contributors. All rights reserved. https://pylint.pycqa.org/en/latest/index.html#, and is used under the Python Software Foundation License Version 2. Examples, recipes, and other code in the Pylint documentation are additionally licensed under the Zero Clause BSD License.