On Thu, Aug 16, 2012 at 12:00 PM, Aaron Brady <castiro...@gmail.com> wrote: > The inconsistency is, if we remove an element from a set and add another > during iteration, the new element might appear later in the iteration, and > might not, depending on the hash code; therefore comparing the size of the > set between iterations isn't adequate. Example:
It can be more than just the new element. For example, here the entire set is repeated (Python 3.2): >>> s = set(range(8, 13)) >>> it = iter(s) >>> from itertools import islice >>> list(islice(it, 5)) # avoid exhausting the iterator [8, 9, 10, 11, 12] >>> s.add(13) >>> s.remove(13) >>> list(it) [8, 9, 10, 11, 12] This occurs because the addition of the sixth item triggers a resize of the underlying hash table, and the existing items, which were originally in slots 0-4, are now in slots 8-12. -- http://mail.python.org/mailman/listinfo/python-list
