On every third iteration in PHP

I would like to output some specific HTML on the third iteration of a loop in PHP. Here is my code:

<?php foreach ($imgArray as $row): ?>
   <div class="img_grid"><?= $row ?></div>
<?php endforeach; ?>

On the third iteration of this loop, Instead of displaying:

<div class="img_grid"><?= $row ?></div>

I would like to display:

<div class="img_grid_3"><?= $row ?></div>

I would like to end up with this if my array looped 8 times:

   <div class="img_grid">[some html]</div>
   <div class="img_grid">[some html]</div>
   <div class="img_grid_3">[some html]</div>
   <div class="img_grid">[some html]</div>
   <d开发者_运维知识库iv class="img_grid">[some html]</div>
   <div class="img_grid_3">[some html]</div>
   <div class="img_grid">[some html]</div>
   <div class="img_grid">[some html]</div>

Thanks

---

Assuming $imgArray is an array and not an associative array (i.e. it has numeric indices), this is what you want:

<?php foreach($imgArray as $idx => $row): ?>
  <?php if($idx % 3 == 2): ?>
    <div class="img_grid_3"><?php echo $row; ?></div>
  <?php else: ?>
    <div class="img_grid"><?php echo $row; ?></div>
  <?php endif; ?>
<?php endforeach; ?>

You could tighten it up a bit like this:

<?php foreach($imgArray as $idx => $row):
        if($idx % 3 == 2) {
          $css_class = 'img_grid_3';
        } else {
          $css_class = 'img_grid';
        }
?>
  <div class="<?php echo $css_class; ?>"><?php echo $row; ?></div>
<?php endforeach; ?>

Or even more (some folks would just go with a ternary conditional inline in the HTML), but the law of diminishing returns kicks in eventually with regard to readability. Hopefully this gives you the right idea, though.