# a zip() function would be handy here (see. Language::Functional)
my $i      = 1;
my %months = map { $i++ => $_ }
                 qw(January February March April May June 
                    July August September October November December);


printf "%2s: %s\n", $_, $months{ sprintf '%d', $_ }
  for qw( 09 4 06 11 );

__output__

09: September
 4: April
06: June
11: November