next if ($element eq $compare);

##</code><code>##

($front, $back) = split /:/, $compare;
if ( $compare =~ /:$back$/ ) {
  # do something
}

##</code><code>##

$moduloc = () = $compare =~ /X(\d+):/; # Grab the divisor.
$moduloe = () = $element =~ /X(\d+):/; # Grab the other one.
next if ( not $modulo ); # otherwise zero always matches.
if ( not ($moduloe)%($moduloc) ) {
  # Do something.
}