Hi,
Suppose I have this array: 

 my %hash2 =(
           '1' => 2,
           '3' => 5,
           '4' => 2,);

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Where the key is index, and the values is the count of that index.
How can I create the new set hash, so that it gives:
$VAR1  = 
{
          '3-3' => 5,
          '3-4' => 10,
          '1-1' => 2,
          '3-1' => 10,
          '1-4' => 4,
          '4-4' => 2,#ends here
};

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My current code: 
use strict;
use warnings;
use Data::Dumper;

#print Dumper \%hash2;
my %spair = ();
my $prod;
foreach my $si (keys %hash2)
  {
    foreach my $sn (keys %hash2)
      {    
           if ($si == $sn)
         {
               $prod = $hash2{$si};
         }
           else
         { $prod = $hash2{$si}*$hash2{$sn};
         }
           $spair{$si."-".$sn} = $prod;  
      }
  }
print Dumper \%spair;

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give this which is not as desired:
$VAR1 = {
          '3-3' => 5,
          '3-4' => 10,
          '1-1' => 2,
          '3-1' => 10,
          '1-4' => 4,
          '4-4' => 2,
          '4-1' => 4, #repeat
          '1-3' => 10,#repeat
          '4-3' => 10 #repeat
        };

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As you can see it repeats 1-4 and 4-1, etc. which actually should only occur once. How can I modify my code so that we can get the expected result?

Regards,
Edward WIJAYA

In reply to Self-Looping over hash - how to remove duplicate by monkfan

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