-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Martin v. Löwis wrote: >> Hmm, perhaps when using sets as work queues? > > A number of comments: > > - it's somewhat confusing to use a set as a *queue*, given > that it won't provide FIFO semantics. > - there are more appropriate and direct container structures > available, including a dedicated Queue module (even though > this might be doing to much with its thread-safety). > - if you absolutely want to use a set as a work queue, > then the .pop() method should be sufficient, right? > > Regards, > Martin
We were using sets to track the tips of a graph, and to compare whether one node was an ancestor of another one. We were caching that answer into frozensets, since that made them immutable. If res = heads(node1, node2) if len(res) == 1: # What is the 'obvious' way to get the node out? I posit that there *isn't* an obvious way to get the single item out of a 1-entry frozenset. for x in res: break list(res)[0] set(res).pop() iter(res).next() [x for x in res][0] x, = res # I didn't think of this one before recently Are all answers, but none of them I would consider *obvious*. At the least, none of them are obviously better than another, so you look into the performance characteristics to give you a reason to pick one over the other. res.get() would be a fairly obvious way to do it. Enough that I would probably never have gone searching for any of the other answers. Though personally, I think I would call it "set.peek()", but the specific name doesn't really matter to me. John =:-> -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (Cygwin) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAkrlB4MACgkQJdeBCYSNAAN0lQCgrtyXWlqIbjj01qB4AKPhKrMq QH8An0z2gCWZHoceEJsqRJOUdEl/VLTB =fJXI -----END PGP SIGNATURE----- _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
