in reply to Difference between two arrays

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

Replies are listed 'Best First'.
Re^2: Difference between two arrays
by Anonymous Monk on Mar 23, 2006 at 05:36 UTC
    This will work only for the elements which are removed in the front.
    my $before = [qw(1 2 3 4 5 6 7 8 9 10)];
my $after  = [qw(1 2 4 3 5 6 7 8 9 10)];
$k=0;
for($i=0;$i<=@$before;$i++)
{
    for($j=$k;$j<=@$after;$j++)
       {
        if(@$before[$i] eq @$after[$j] and $i==$j)
          {
            $i++;$k++;
          }
        if(@$before[$i] eq @$after[$j] and $i!=$j)
          {
            print "element @$before[$i]  is moved to the position ",$j
++1;
            $i=@$before+1;
            last;
          }
       }    
}

__DATA__

element 3 is moved to the position 4

    [download]
    Any comments to this code.
[reply]
[d/l]

In Section Seekers of Perl Wisdom