On Tue, Mar 10, 2009 at 11:54 AM, Dan Cech <dc...@phpwerx.net> wrote: > Chris Snyder wrote: >> Add a random number to a sufficiently deep timestamp (microseconds) >> and you will have a non-repeating random number. But you can't shorten >> it to 8 characters or whatever -- you have to keep the full timestamp >> in order to maintain non-repeatability. > > Not really, if you add a random number then you can easily end up with 2 > results that are the same unless the frequency with which you generate > numbers is less than the variation you're introducing, and at that point > why bother with the random number at all...
Oh yeah, I meant "concatenate" not "add". Doing something like $random = $microtime . "_" . rand( 0, 256 ); gives you non-repeating pseudo-randomness. Whether that's random enough for some applications is another issue, but it won't repeat as long as the timestamp used for $microtime doesn't roll over to 0. _______________________________________________ New York PHP User Group Community Talk Mailing List http://lists.nyphp.org/mailman/listinfo/talk http://www.nyphp.org/show_participation.php
