Doesn't really address your overall efficiency question, but I see over and over people forgetting (or never having known) that push takes a LIST, not just a single scalar: 
        while ( $group->{$advert} > 0 ) {
            push( @rndselect, $advert );
            $group->{$advert}--;
        }#while

[download]
becomes 
        push( @rndselect, ($advert) x $group->{$advert} );

[download]
--
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In reply to Re: Weighted random selection by ysth
in thread Weighted random selection by cosmicperl

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