You know what: I have no idea why my version is faster. I didn't specifically write it that way to get better performance: to me it just seemed the obvious way to do it.

But that's precisely what I love about Perl: as a general rule, the more Perlishly you code, the faster the code runs!

Sorry not to be able to offer you enlightenment, but when it comes to Perl internals, I am (quite happy to remain) an utter novice.

;-)