Duplicate Term with get_the_terms()

Question

I'm having some difficulty listing a custom post type with unique category/taxonomy headings. I have a ACF reverse relationship and currently have two articles under category 1 and one article under category 2. Next, I'm attempting to loop through each category and list them out like so:

Category 1

• article
• article

Category 2

• article

However, what the below is returning is:

Category 1

• article

Category 1

• article

Category 2

• article

      $research = get_posts(array(
          'post_type' => 'research-data',
          'meta_query' => array(
              array(
                  'key' => 'show_on_page',
                  'value' => '"' . get_the_ID() . '"', // matches exaclty "123", not just 123. 
                  'compare' => 'LIKE'
                  )
              )
          ));
  
          ?>
          <?php if( $research ): ?>
          <h3> Research &amp; Data</h3>
          <?php foreach( $research as $r ): ?>
  
          <!-- Begin custom tax loop -->
          <?php
  
          $categories = get_the_terms($r->ID, 'research-cats', $term_args);
  
          $c_terms = array(); 
  
          foreach ( $categories as $term ) {
              $c_terms[] = $term->name;
          }
  
          $unique_cat = array_unique($c_terms);
  
          //print_r($unique_cat);
  
          ?>
  
          <strong><?php echo $unique_cat[0]; ?></strong>
  
          <ul>
              <?php
              $posts = get_posts(array(
                  'post_type' => 'research-data',
                  'orderby' => 'menu_order',
                  'order' =>  'ASC',
                  'post__in' => array($r->ID),
                  'nopaging' => true,
                  ));
  
              foreach($posts as $post) :
                  setup_postdata($post);  
              ?>
  
              <li><a href="<?php the_permalink(); ?>"><?php the_title(); ?> </a></li>
  
          </ul>
              <?php endforeach; ?>
   <?php endforeach; ?>
  <?php endif; ?>
  

Any thoughts? This is driving me nuts!

Answer 1

$research = get_posts(array(
        'post_type' => 'research-data',
        'meta_query' => array(
            array(
                'key' => 'show_on_page',
                'value' => '"' . get_the_ID() . '"', // matches exaclty "123", not just 123. 
                'compare' => 'LIKE'
                )
            )
        ));
$previous_category = '';
        ?>
        <?php if( $research ): ?>
        <h3> Research &amp; Data</h3>
        <?php foreach( $research as $r ): ?>

        <!-- Begin custom tax loop -->
        <?php

        $categories = get_the_terms($r->ID, 'research-cats', $term_args);

        $c_terms = array(); 

        foreach ( $categories as $term ) {
            $c_terms[] = $term->name;
        }

        $unique_cat = array_unique($c_terms);

        //print_r($unique_cat);

        ?>

        <?php if($previous_category !== $unique_cat[0]) { ?><strong><?php $previous_category = $unique_cat[0]; echo $unique_cat[0]; ?></strong><?php } ?>

        <ul>
            <?php
            $posts = get_posts(array(
                'post_type' => 'research-data',
                'orderby' => 'menu_order',
                'order' =>  'ASC',
                'post__in' => array($r->ID),
                'nopaging' => true,
                ));

            foreach($posts as $post) :
                setup_postdata($post);  
            ?>

            <li><a href="<?php the_permalink(); ?>"><?php the_title(); ?> </a></li>

        </ul>
            <?php endforeach; ?>
 <?php endforeach; ?>
<?php endif; ?>

Without knowing how your are getting your data and what the format of $research is it would be hard but I am guessing that if you use the above with the addition of $previous_category variable it should prevent this behaviour

Answer 2

I ended up starting over with this and it works as expected:

http://support.advancedcustomfields.com/forums/topic/duplicate-taxonomy-with-reverse-relationship/#post-30741