foreach (@t_loop) {
   my $label = $_->{label};

   my $value;
   if (exists($_->{value_loop})) {
      $value = join(' ', map { $_->{value} } @{$_->{value_loop});
   } else {
      $value = $_->{value};
   }

   $final .= "$label=$value\n";
}

##</code><code>##

%t_loop = (
   Dow => [ 'Sun', 'Mon', 'Tue', 'Wed' ],
);

##</code><code>##

%t_loop = (
   UK => 'Country',
);

##</code><code>##

while (my ($key, $val) = each %t_loop) {
   $val = join(' ', @$val)
      if ref $val;

   $final .= "$key=$val\n";
}