I think this is a little different approach. Since the original array was in ascending order to find the swapped elements we just need to find the descending step in the $after array. Once you have the location, you just need to determine if it moved right or left.
my $after = [qw(2 3 4 1 5 6 7 8 9 10)];
for (my $i = 1; $i < scalar($after); $i++){
   my $diff = after->[$i-1] - $after->[$i];
   if($diff > 0){
      if($diff > $i){
         printf "$after->[$i-1] moved to position %d\n",($i-1);
      }
      else{
         print "$after->[$i] moved to position $i\n";
      }
      last;
   }
}

[download]
The output would be:
1 moved to position 3

In reply to Re: Difference between two arrays by Anonymous Monk
in thread Difference between two arrays by rafl

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