use strict;
use warnings; 

use Data::Dumper qw/Dumper/;
my %a;
#%a = map { $a{$_} => 1 unless undef, 0..5 } 0..11;
#%a = map { $a{$_} , 1 unless undef, 0..5 } 0..11;
%a = map { 1 unless undef, 0..5 } 0..11;
print Dumper \%a;