Great that you found a solution yourself

Since you didn't follow your own idea of using sorting to identify doubles the sort step is now useless.

To follow your original plan you would have to do something like this:

my $previous="";
foreach my $element ( @sorted_array_q3 )
{
  if ( $element ne $previous )
  {
     push( @unique_array, $element );
  }
  $previous= $element;
}
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