use Data::Dumper;
my %hash = do { my $i = 0; map { $_ => $i++ } qw/Sun Mon Tue Wed Thr Fri Sat/ };
print Dumper \%hash;
while(my ($k, $v) = each %hash){ $k = lc($k); $v *= 2 };
print Dumper \%hash;

$VAR1 = {
          'Mon' => 1,
          'Tue' => 2,
          'Fri' => 5,
          'Thr' => 4,
          'Wed' => 3,
          'Sat' => 6,
          'Sun' => 0
        };
$VAR1 = {
          'Mon' => 1,
          'Tue' => 2,
          'Fri' => 5,
          'Thr' => 4,
          'Wed' => 3,
          'Sat' => 6,
          'Sun' => 0
        };