Hi, if I understood correctly your problem you could just create a hash whose keys are made of the concatenated start and end, with a appropriate separator, e.g. "7-12". The values can be anything, it could be 1. Then you just check for the existence of the hash for the concatenated pair of numbers. 
if (exists $hash{"start-$end"} ) {
    # do something
}

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In reply to Re: Request help on optimizing a loop for looking up numbers by Laurent_R
in thread Request help on optimizing a loop for looking up numbers by VincentK

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