%Tape_Cat should be hash whose keys are the tape labels Each key contains an array of refs. Each ref in this array is anarray ref containing Protection, Location, and Pool

Looks like:

%Tape_Cat->Label->Record1 { Protection, Location, Pool }
                 |->Record2 { Protection, Location, Pool }
                 .
                 .
                 |->Recordn {Protection, Location, Pool }

I want to determine the value n and elminate those tapelabels with onl
+y one record.
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I think your suggestion will place only one record , whichever is found last in %Tape_Cat. Am I missing the point?