Yeah, I also like the idea of using strings instead of arrays. When I read the problem, my first thought was to try something like... 
$genome=~s/(.)(?=(.))/++$count{$1.$2} and undef/eg;

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...does anyone else tend to (ab)use the replacement operator as sort of a map which works on strings?

In reply to using s/// as map? by sleepingsquirrel
in thread how can I speed up this perl?? by Anonymous Monk

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