Your code:

sort keys { $a <=> $b } %hash

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Is incorrect. Assuming the groups really look like "AA01" and "GF02", and assuming you want them in alphabetical order, and assuming these are in the hash %hash, this is what you want: 
sort { $a cmp $b } keys %hash

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In reply to Re: Some advice regaring sorting and hashes by markkawika
in thread Some advice regaring sorting and hashes by tsk1979

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