html5 - Compare data-ids with jquery -

i have articles shown 2 times , want hide 1 of them jquery. both have same data-id want find way compare them (data-id="134"). also, won't know id's can't write (if data-id === 134 example) there way this? code right now:

    var article1_id = $('.older_articles ajax_article active').data("id");     var article2_id= $('.featured_article').data("id");      if article1_id === article2_id {         $(article1_id).css('display', 'none');     } else {         $(article1_id).css('display', 'block');     } 

if understand correctly can in 1 line of jquery. hide elements within .old_articles have data-id attribute matching of featured article...

$('.older_articles [data-id="' + $('.featured_article').data('id') + '"]').css('display', 'none');

example...

$('.older_articles [data-id="' + $('.featured_article').data('id') + '"]').css('opacity', '0.5');

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>    <div class="older_articles">      <h4>old articles</h4>      <div data-id="134">featured article duplicate - data-id 134</div>      <div data-id="135">non-duplicated article- data-id 135</div>  </div>    <div>      <h4>featured articles</h4>      <div class="featured_article" data-id="134">i'm featured! - data-id 134  </div>

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if need hide multiple elements can use .each() loop through of articles...

$('.featured_article').each(function() {      $('.older_articles [data-id="' + $(this).data('id') + '"]').css('opacity', '0.5');  });

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>  <div class="older_articles">      <h4>old articles</h4>      <div data-id="134">article - data-id 134</div>      <div data-id="135">article - data-id 135</div>      <div data-id="137">article - data-id 137</div>      <div data-id="138">article - data-id 138</div>  </div>    <div>      <h4>featured articles</h4>      <div class="featured_article" data-id="134">i'm featured! - data-id 134      <div class="featured_article" data-id="135">i'm featured! - data-id 135      <div class="featured_article" data-id="136">i'm featured! - data-id 136      <div class="featured_article" data-id="138">i'm featured! - data-id 138  </div>