Message 177599 - Python tracker

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Author	wim.glenn
Recipients	docs@python, wim.glenn
Date	2012-12-16.13:53:54
SpamBayes Score	-1.0
Marked as misclassified	Yes
Message-id	<1355666035.13.0.877787561314.issue16697@psf.upfronthosting.co.za>
In-reply-to

Content
Any object that supports the in operator can be passed as the choices value, so dict objects, set objects, custom containers, etc. are all supported. (from http://docs.python.org/dev/library/argparse.html#choices ) Actual behaviour is contradicted by the docs - it seems the container must additionally be iterable. When using a custom container, argparse b0rks on trying to iterate through choices. Using a metavar prevents this, but it still breaks on cases where the element is not in the container. More details here: http://stackoverflow.com/questions/13833566/python-argparse-choices-from-an-infinite-set

Any object that supports the in operator can be passed as the choices value, so dict objects, set objects, custom containers, etc. are all supported.  (from  http://docs.python.org/dev/library/argparse.html#choices )

Actual behaviour is contradicted by the docs - it seems the container must additionally be iterable.  When using a custom container, argparse b0rks on trying to iterate through choices.  Using a metavar prevents this, but it still breaks on cases where the element is not in the container.  

More details here:  
http://stackoverflow.com/questions/13833566/python-argparse-choices-from-an-infinite-set

History
Date	User	Action	Args
2012-12-16 13:53:55	wim.glenn	set	recipients: + wim.glenn, docs@python
2012-12-16 13:53:55	wim.glenn	set	messageid: <1355666035.13.0.877787561314.issue16697@psf.upfronthosting.co.za>
2012-12-16 13:53:55	wim.glenn	link	issue16697 messages
2012-12-16 13:53:54	wim.glenn	create