my %ntests;  $ntests{$_} = 0 for @tests;

##</code><code>##

@{ \my %ntests }{ @tests } = (0)x@tests; # :)

##</code><code>##

my $mol = '';
$mol = 'forty two'
    if  42 == $n;

##</code><code>##

my $mol =
    ! defined $n
        ? 'n/a' :
    42 == $n
        ? 'forty two'
        : '';