my    $fh = defined $hash{$ita}[0] &&
            defined $hash{$ita}[1] ? $out : $out1;

print $fh "$ita => ",
           join(',', map { $_ // () } @{ $hash{$ita} }),
          "\n";

##</code><code>##

17:42 >perl -MData::Dump -wE "my @c = qw(a e i o u); @c = map { $_ eq 'i' ? undef : $_ } @c; dd \@c;"
["a", "e", undef, "o", "u"]

17:44 >perl -MData::Dump -wE "my @c = qw(a e i o u); @c = map { $_ eq 'i' ? () : $_ } @c; dd \@c;"
["a", "e", "o", "u"]

17:44 >

##</code><code>##

print $fh "$ita => ",
           join(',', grep { defined } @{ $hash{$ita} }),
          "\n";