https://github.com/python/cpython/commit/dd0840bf67e194ab64f340b8a7fbda24cb25e177 commit: dd0840bf67e194ab64f340b8a7fbda24cb25e177 branch: main author: Hans Then <[email protected]> committer: savannahostrowski <[email protected]> date: 2025-09-17T15:25:17Z summary:
gh-132558: Improve `argparse` docs on combining `type` and `choices` (#133827) Co-authored-by: Savannah Bailey <[email protected]> files: M Doc/library/argparse.rst diff --git a/Doc/library/argparse.rst b/Doc/library/argparse.rst index ef8242f5f780f5..efa936da10208d 100644 --- a/Doc/library/argparse.rst +++ b/Doc/library/argparse.rst @@ -1142,16 +1142,21 @@ if the argument was not one of the acceptable values:: game.py: error: argument move: invalid choice: 'fire' (choose from 'rock', 'paper', 'scissors') -Note that inclusion in the *choices* sequence is checked after any type_ -conversions have been performed, so the type of the objects in the *choices* -sequence should match the type_ specified. - Any sequence can be passed as the *choices* value, so :class:`list` objects, :class:`tuple` objects, and custom sequences are all supported. Use of :class:`enum.Enum` is not recommended because it is difficult to control its appearance in usage, help, and error messages. +Note that *choices* are checked after any type_ +conversions have been performed, so objects in *choices* +should match the type_ specified. This can make *choices* +appear unfamiliar in usage, help, or error messages. + +To keep *choices* user-friendly, consider a custom type wrapper that +converts and formats values, or omit type_ and handle conversion in +your application code. + Formatted choices override the default *metavar* which is normally derived from *dest*. This is usually what you want because the user never sees the *dest* parameter. If this display isn't desirable (perhaps because there are _______________________________________________ Python-checkins mailing list -- [email protected] To unsubscribe send an email to [email protected] https://mail.python.org/mailman3//lists/python-checkins.python.org Member address: [email protected]
