Sorry, I meant to say "That's why the looping is needed if you use a hash."

Of course, you could just do

sub get_score {
   my ($score) = @_;
   return 'A' if $score >= 90;
   return 'B' if $score >= 80;
   return 'C' if $score >= 70;
   return 'D' if $score >= 60;
   return 'F';
}
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