New submission from Steven D'Aprano <steve+pyt...@pearwood.info>:
There is a long-standing tradition, going back to Python 1.x days before we had dedicated True and False values, to use the lowercase "true" and "false" to mean *any value that duck-types as True* and *any value that duck-types as False* in a boolean context. Other terms for this same concept include "truthy/falsey" and using true/false as adjectives rather than nouns, e.g. "a true value". But I am not sure whether this is actually written down anywhere in the documentation. It would be useful for those who are not aware of the convention (e.g. beginners and people coming from other languages) if the Glossary had entries for lowercase "true" and "false" that explained the usage and referred back to PEP 285. See for example #46882 where this came up. I suggest something like the following: boolean context Code such as ``if condition:`` and ``while condition:`` which causes the expression ``condition`` to be evaluated as if it were a :class:`bool`. false Any object which evaluates to the :class:`bool` singleton ``False`` in a :term:`boolean context`. Informally known as "falsey". See :term:`true` and :pep:`285`. Among the builtins , false values include ``None``, empty containers and strings, and zero numbers. true Any object which evaluates to the :class:`bool` singleton ``True`` in a :term:`boolean context`. Informally known as "truthy". See :term:`false` and :pep:`285`. Among the builtins , true values include non-empty containers and strings, non-zero numbers (including NANs), and all other objects by default. ---------- assignee: docs@python components: Documentation messages: 414204 nosy: docs@python, steven.daprano priority: normal severity: normal status: open title: Add glossary entries to clarify the true/True and false/False distinction type: enhancement versions: Python 3.10, Python 3.11, Python 3.7, Python 3.8, Python 3.9 _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue46883> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
