If you want to conditionally include things in a list, try the x!! operator combo:

my $pi = 0;
my $life = 'isgood';
my $foo = 1;
my $aref = [ (3,1,4) x !!($pi), (42) x !!($life), ('bar', 'baz') x !!(
+$foo)  ];
print Dumper $aref;
[download]

$VAR1 = [
          42,
          'bar',
          'baz'
        ];
[download]