$result = [ 
  { mag_name => "mag1", issue_num => "01", article => "art1" },
  { mag_name => "mag1", issue_num => "01", article=> "art2" },
  { mag_name => "mag1", issue_num => "02", article=> "art1" },
  { mag_name => "mag1", issue_num => "02", article=> "art2" },
  { mag_name => "mag3", issue_num => "01", article=> "art1" }
] ;

##</code><code>##

$data = [
  {
     'magazine_name' => 'mag1',
     'issue_loop' => [
       {
         issue_number => '01',
         article_loop => [
            { article_name => 'art1' }
            { article_name => 'art2' }
            ],
       },
       {
         issue_number => '02',
         article_loop => [
           { article_name => 'art1' }
           { article_name => 'art2' }
           ]
        },
        {
         'mag_name' => 'mag2',
         'issue_loop' => [
            {
            issue_number => '01',
            article_loop => [
              { article_name => 'art1' },
              { article_name => 'art2' }
             ]
             },
             {
               issue_number => '02',
               article_loop => [
                  { article_name => 'art1' },
                  { article_name => 'art2' }
              ]
          }
       ] ;