You might use this in order to eliminate the duplicates from an array:

my @items = qw ( 1 2 2 2 1 3 3 2 3 4 3 1 2 5 );
my $x, $y;

$x = 0;
foreach $a (@items) {
   $y = 0;
   foreach $b (@items) {
      if ($a == $b) {
         next;
      }
      if ($items[$x] == $items[$y]) {
          splice(@items, $y, 1);
      }
      $y++;
   }
   $x++;
}
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Originally posted as a Categorized Answer.