Dear all, I have several arrays within which the order of the elements are important. I found this easier to code than a multi-tier hash. However, when I sort one array, I would like to change the order of the other arrays likewise.

I can create a hash that stores the former index of an element, but the elements in any of the arrays are non-unique. It seems to me that I'll have to do this: 

my @array=('C','B','A','C');
my %hash=();
for(my $i=0;$i<scalar(@array);$i++){
    $hash{$i}=$array[$i];
}

@array=sort @array;
my %found=();
my @sorted_indexes=();
foreach my $k(sort {$a <=> $b } keys %hash){
   for(my $i=0;$i<scalar(@array);$i++){
      if($array[$i] eq $hash{$k} && !exists($found{$hash{$k}}){
         print $hash{$k}."-> Former: ".$k." Latter: ".$i."\n";
         $found{$hash{$k}}=1;
         push(@sorted_indexes,$i);
      }
   }
}

[download]
The above code should give me an array which indicates, for every index, the previous index. I am sure however that there is an easier solution that I've missed, perhaps involved map, of which i've no experience.

Many thanks
Sam

In reply to Remembering original order of an array by seaver

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