在wordpress中循环分类

i have some trouble with a loop. I need to display some div every 6 iterations

<div class="category_block">    
<?php foreach (get_categories() as $cat) : ?>
    <div class="category_item">
        <img src="<?php echo z_taxonomy_image_url($cat->term_id); ?>" />
        <a href="<?php echo get_category_link($cat->term_id); ?>"><?php echo $cat->cat_name; ?></a>
        <span><?php echo $cat->category_count; ?></span>
    </div>
<?php endforeach; ?>
</div>

What i need to do?

You can create some variable and can check that variable's value. If that's 6, 12, or 18 etc ... then you can put your etc ... have a code example below:

<div class="category_block">    
<?php $counter = 0; ?>
<?php foreach (get_categories() as $cat) :
$counter++;
?>

    <div class="category_item">
     <?php if($counter % 6 == 0) {>
     <div class="custom-div"></div> 
    <?php } ?>
        <img src="<?php echo z_taxonomy_image_url($cat->term_id); ?>" />
        <a href="<?php echo get_category_link($cat->term_id); ?>"><?php echo $cat->cat_name; ?></a>
        <span><?php echo $cat->category_count; ?></span>
    </div>
<?php endforeach; ?>
</div>

Hope, that solves your issue.