.. _modified-iterating-set:

modified-iterating-set / E4703
==============================

**Message emitted:**

``Iterated set '%s' is being modified inside for loop body, iterate through a copy of it instead.``

**Description:**

*Emitted when items are added or removed to a set being iterated through. Doing so raises a RuntimeError.*

**Problematic code:**

.. literalinclude:: /data/messages/m/modified-iterating-set/bad.py
   :language: python

**Correct code:**

.. literalinclude:: /data/messages/m/modified-iterating-set/good.py
   :language: python





Created by the `modified_iteration <https://github.com/pylint-dev/pylint/blob/main/pylint/checkers/modified_iterating_checker.py>`__ checker.