c:\@Work\Perl>perl -wMstrict -MData::Dump -le
"my @data = 1 .. 4;
 dd \@data;
 ;;
 my @results;
 foreach (@data) {
   $_ = $_ * 13;
   push @results, $_;
   }
 ;;
 dd \@data;
 dd \@results;
"
[1 .. 4]

[13, 26, 39, 52]

[13, 26, 39, 52]