On 3/29/06, Adam DePrince <[EMAIL PROTECTED]> wrote: > > > set interface where we could have a __container__/__view__/__set__ > > Why would I call a method to get a view on an object when the object can > just as well implement the view? The *only* time we want to call a > method to get a view is when there is not one, single, completing > definition of the object's canonical perspective should be. >
That's my point. What are we gaining by trying to augment iterators or come up with some specified way to know if something contains something else when we can get it off of the object itself. Although, as Nick pointed out, dicts have multiple views of their data. But if you just want to know if a key or value exists, then you can either use a dict's __contains__ for keys or create a set to use for values. That's what a view will end up having to do anyway underneath the covers, so I don't know if we are going to get much benefit from going through this beyond just saying dict.value_view() returns a set of the values in a dict. Don't know if we really need to go through all of this formality. > List has a single obvious view. If you really want to see a list as a > setview, just pretend it doesn't implement OrderedView and > CollectionView. Down-casting by neglect works fine. > > Dict doesn't, there are 4 possiable views. The mapping view provided > directly by the dict, and keys/values/items. Four? In terms of "atomic" data views, there are keys and values. Items could be counted, but that is just a way to pair the different types of data in a dict together so I don't know if I would count it as a view, let alone whether it would be useful outside of an iterator. But counting the dict itself is just counting the key view twice since you can get all of that data directly from the dict without needing a view as you pointed out above. -Brett _______________________________________________ Python-3000 mailing list Python-3000@python.org http://mail.python.org/mailman/listinfo/python-3000 Unsubscribe: http://mail.python.org/mailman/options/python-3000/archive%40mail-archive.com
