On Fri, 07 Sep 2007 08:47:58 -0700, Paul Rubin wrote: > Paul Rubin <http://[EMAIL PROTECTED]> writes: >> def unique_id(): >> return os.urandom(10).encode('hex') > > Sorry, make that 32 or 40 instead of 10, if the number of id's is large, > to make birthday collisions unlikely.
I did a small empirical test, and with 16 million ids, I found no collisions. However, I did find that trying to dispose of a set of 16 million short strings caused my Python session to lock up for twenty minutes until I got fed up and killed the process. Should garbage-collecting 16 million strings really take 20+ minutes? > If you don't want the id's to be that large, you can implement a Feistel > cipher using md5 or sha as the round function pretty straightforwardly, > then just feed successive integers through it. That also guarantees > uniqueness, at least within one run of the program. I have some sample > code around for that, let me know if you need it. I'm not sure that I need it, but I would certainly be curious to see it. Thanks, -- Steven. -- http://mail.python.org/mailman/listinfo/python-list
