Martin MOKREJŠ wrote: > Robert Brewer wrote: > > Martin MOKREJŠ wrote: > > > >> I have sets.Set() objects having up to 20E20 items, > >>each is composed of up to 20 characters. Keeping > >>them in memory on !GB machine put's me quickly into swap. > >>I don't want to use dictionary approach, as I don't see a sense > >>to store None as a value. The items in a set are unique. > >> > >> How can I write them efficiently to disk? > > > > > > got shelve*? > > I know about shelve, but doesn't it work like a dictionary? > Why should I use shelve for this? Then it's faster to use > bsddb directly and use string as a key and None as a value, I'd guess.
If you're using Python 2.3, then a sets.Set *is* implemented with a dictionary, with None values. It simply has some extra methods to make it behave like a set. In addition, the Set class already has builtin methods for pickling and unpickling. So it's probably faster to use bsddb directly, but why not find out by trying 2 lines of code that uses shelve? The time-consuming part of your quest is writing the timed test suite that will indicate which route will be fastest, which you'll have to do regardless. Robert Brewer MIS Amor Ministries [EMAIL PROTECTED] -- http://mail.python.org/mailman/listinfo/python-list
