What is the purpose of using alias in this line alias my $r = $$range[$i];

It was just to shorten code, and play around with Data::Alias a bit. Since LanX showed that the module isn't necessary (because the elements of @_ are already aliases), I removed it and posted an updated getsubset here.

I hope you don't resent me "embellishing" on your script.

Not at all, do whatever you need to figure stuff out, that's why I post publicly :-)