@subnets = {
              {
                 'id' => '1',
                 'location_id' => '30',
                 'subnet' => '255.255.255.0'
               },
                             {
                 'id' => '2',
                 'location_id' => '13',
                 'subnet' => '255.255.254.0'
               },
              {
                 'id' => '3',
                 'location_id' => '19',
                 'subnet' => '255.255.0.0'
               },
          };

@filers_info = {
                 {
                   'id' => '1',
                   'location_id => '19',
                   'info' => 'blah1',
                 },
                 {
                   'id' => '2',
                   'location_id => '30',
                   'info' => 'blah1',
                 },
            };
foreach my $subnet (@subnets) {
   my @found_filers = grep { $_->{'location_id'} == $subnet->{'location_id'} } @filers_info;
  push @total_filers, @found_filers;
        }
@filer_ids = map{$_->{'id'} } @total_filers;