I wouldn't see myself using it for an arbitrary value in the middle of the list, but perhaps for the 0th or -1st (first/last) element of a list that might be empty. Maybe also second-to-first/last if I'm initializing some comparison between sequential items?
Some of the examples don't work with negative indexes, boo. On Tue, Feb 28, 2017 at 12:52 PM, David Mertz <me...@gnosis.cx> wrote: > On Tue, Feb 28, 2017 at 10:10 AM, Sven R. Kunze <srku...@mail.de> wrote: > >> Yes, and easily written as above. What significant advantage would it >> have to spell the above as: >> >> x = alist.get(pos, default_val) >> >> It's a couple characters shorter in the proposed version. I guess I'll >> concede that needing the odd indexing at the end to get the scalar is >> slightly ugly. >> >> 1. advantage: it looks like dict access -> allows duck typing (oh how >> often I'd missed that) >> 2. advantage: no try except >> 3. advantage: no weird workaround with slices and additional item access >> > > How often would you duck-type "access either an integer position or a > named key in a collection?" > > I'm all for duck typing, but it feels like those are a pretty different > pattern. For example, I know that if a list has something at index 10 it > also has something at index 9. I absolutely *do not* know that if a dict > has something at key 'g' it also has something at key 'f'. > > > -- > Keeping medicines from the bloodstreams of the sick; food > from the bellies of the hungry; books from the hands of the > uneducated; technology from the underdeveloped; and putting > advocates of freedom in prisons. Intellectual property is > to the 21st century what the slave trade was to the 16th. > > _______________________________________________ > Python-ideas mailing list > Python-ideas@python.org > https://mail.python.org/mailman/listinfo/python-ideas > Code of Conduct: http://python.org/psf/codeofconduct/ >
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