Wordpress PHP split (wrap) elements in array into rows

gistfile1.txt

<?php
  $myposts = get_posts( $args ); //Array of posts
  $index = 1;
  $len = count($myposts);
  foreach( $myposts as $post ): setup_postdata($post);
  $post_id = $post->ID;
?>
<?php 
  if( $index%3 === 1): echo '<div class="row">'; //Open row for every 3-rd (change 3 to desired number in one row)
  endif; 
?>
    <div class="single-element <?php echo $index; ?>">
    </div>
    
<?php 
  if( $index%3 === 0 || $index === $len): echo '</div><!-- end row -->'; // Close row for every 3rd (change to desired number) OR last
  endif; 
  
  $index++;
  endforeach;
?>