use strict;
use warnings;

use Data::Dumper;

my @data = (
   {
       id   => q{1},
       name => q{Tom},
       sex  => q{Male},
   }, 
   {
       id   => q{2},
       name => q{Harry},
       sex  => q{Male},
   }, 
   {
       id   => q{3},
       name => q{Pam},
       sex  => q{Female},
   }, 
   {
       id   => q{4},
       name => q{Dick},
       sex  => q{Male},
   }
   );

my $rhBySex = { Male => [], Female => [] };

push @{ $rhBySex->{ $_->{ sex } } },
   { name => $_->{ name }, id => $_->{ id } }
   for @data;

print Data::Dumper->Dumpxs( [ $rhBySex ], [ qw{ rhBySex } ] );