On Thu, Oct 15, 2009 at 7:05 PM, Anthony Tolle <anthony.to...@gmail.com> wrote: > I wrote a quick subclass of set that does something similar, but uses > just one function for the object uniqueness: > > class MySet(set): > def __init__(self, iterable = (), idfunc = lambda x: x): > self.idfunc = idfunc > self.ids = set() > for item in iterable: > self.add(item) > > def add(self, item): > id = self.idfunc(item) > if id not in self.ids: > self.ids.add(id) > set.add(self, item)
Yes, what you've got there provides the interface of what I want. And no doubt we could concoct countless ways to implement some version of this. However, if set itself accepted an alternate hash function, then I could do it with no extra overhead. Consider your implementation: it requires an extra set (extra space) and an extra lookup on many operations (extra time.) My original hope was to not have to do that. Austin -- http://mail.python.org/mailman/listinfo/python-list
