On 9 Jun 2014 10:04, "Raymond Hettinger" <raymond.hettin...@gmail.com> wrote: > > > On Jun 7, 2014, at 6:25 AM, R. David Murray <rdmur...@bitdance.com> wrote: > >>> I guess I could duck-type it based on the _fields attribute but that >>> feels implicit and fragile. >>> >>> What do you guys suggest? >> >> >> I seem to remember a previous discussion that concluded that duck typing >> based on _fields was the way to go. (It's a public API, despite the _, >> due to name-tuple's attribute namespacing issues.) > > > Yes. That is the recommended approach. > > IIRC that was Guido's suggestion rather than creating an abstract > base class for a named tuple (any tuple-like class with indexable > elements that are also accessible using named attributes).
Given the somewhat periodic recurrence of the question, might it be worth making an ABC after all, with "subclass of tuple with a _fields attribute" as its default check? "isinstance(obj, collections.NamedTupleABC)" is quite a bit more self-documenting than "isinstance(obj, tuple) and hasattr(obj, '_fields')" Cheers, Nick. > > > Raymond > > > _______________________________________________ > Python-Dev mailing list > Python-Dev@python.org > https://mail.python.org/mailman/listinfo/python-dev > Unsubscribe: https://mail.python.org/mailman/options/python-dev/ncoghlan%40gmail.com >
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