.. _too-many-positional-arguments:

too-many-positional-arguments / R0917
=====================================

**Message emitted:**

``Too many positional arguments (%s/%s)``

**Description:**

*Used when a function has too many positional arguments.*

**Problematic code:**

.. literalinclude:: /data/messages/t/too-many-positional-arguments/bad.py
   :language: python

**Correct code:**

.. literalinclude:: /data/messages/t/too-many-positional-arguments/good.py
   :language: python

**Configuration file:**

.. literalinclude:: /data/messages/t/too-many-positional-arguments/pylintrc
    :language: ini

**Additional details:**

Good function signatures don’t have many positional parameters. For almost all
interfaces, comprehensibility suffers beyond a handful of arguments.

Positional arguments work well for cases where the the use cases are
self-evident, such as unittest's ``assertEqual(first, second, "assert msg")``
or ``zip(fruits, vegetables)``.

There are a few exceptions where four or more positional parameters make sense,
for example ``rgba(1.0, 0.5, 0.3, 1.0)``, because it uses a very well-known and
well-established convention, and using keywords all the time would be a waste
of time.

**Related links:**

- `Special parameters in python <https://docs.python.org/3/tutorial/controlflow.html#special-parameters>`_


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