On Jan 26, 10:04 pm, [EMAIL PROTECTED] wrote: > The PEP 3100:http://www.python.org/dev/peps/pep-3100/ > says: > > Return iterators instead of lists where appropriate for atomic type > methods (e.g. dict.keys(), dict.values(), dict.items(), etc.); iter* > methods will be removed. Better: make keys(), etc. return views ala > Java collections??? > ... > To be removed: > dict.setdefault()? [15] > dict.has_key() method [done] > > I may be sleepy now, but maybe the keys() method too can be removed; > otherwise the following two become really the same: > > print list(adict) > for k in adict: ... > > print list(adict.keys()) > for k in adict.keys(): ...
Alas, the consensus has moved away from simple iterators to less lightweight "views": http://svn.python.org/view/peps/trunk/pep-3106.txt?rev=53096&view=markup "The objects returned by the .keys() and .items() methods behave like sets with limited mutability; the allow removing elements, but not adding them.(...) The object returned by the values() method behaves like a multiset." I for one am not convinced that adding three new types is worth the complexity and the error-proneness of having two new similar-but-not-quite-the-same APIs with sets. Not only iteration is arguably the most common operation on a view, but the cost (in extra keystrokes and runtime performance) of populating any container that the user may need from an iterator is pretty low. George -- http://mail.python.org/mailman/listinfo/python-list
