If you are also concerned with what rating belongs to a particular sequence however (i.e., you supply the sequence and want to know it's rating), you will have to rely on a more complex data structure than an array or a hash. One example is an array reference that contains array references that contain the rating as their first element, and the sequence (as yet another array reference) as the second element:

my $ref = [
    [2, [qw(g a t a c a)]],
    [3, [qw(a t a c a g)]],
    [1, [qw(t a c a g a)]],
];
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print map {join('',@{$_->[1]})."\n"} sort {$a->[0] <=> $b->[0]} @$ref;
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jeffa

L-LL-L--L-LL-L--L-LL-L--
-R--R-RR-R--R-RR-R--R-RR
B--B--B--B--B--B--B--B--
H---H---H---H---H---H---
(the triplet paradiddle with high-hat)