how to add different post class/id in wp loop? [closed]

Question

I want to add class/id into the wordpress loop, but if I add into the loop, it will have the same class/id of each output of posts from the loop.

I know there are conditional statements to add inside the loop to give the first posts or other posts inside the loop the different class/id. But, I don't know how to do that.

For example: I want to give Box 3, Box 6, Box 9, Box 12, Box 15, and a specific boxs a different class/id from others. Please, see the picture.

This is the link of Image: http:// i49.tinypic.com/1s137c.png

Thanks!

Regards!

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I want my out put from the loop look like this: http://pastebin.com/BVkje234

And here is my my code I need to use: http://pastebin.com/7DNVWAC3

I want, Box 3, Box 6, Box 9, Box 12, Box 15 to have the <div class='box-last'>

And Box 1 - Box 15, except above boxs to have <div class='box'>

I use normal loop, and I just want to give the last box of each row to have different class/id from the first two box of the row. Thanks!

Answer 1

<article id="post-<?php the_ID(); ?>" <?php post_class(); ?>>
//Post content
</article>

Is this what you had in mind? or is it something like a sequential numbering?

$cntr = 1;
$posts = get_posts('blahblahblah');
foreach($posts as $post) :
setup_postdata($post);?>
    <li class="<?php echo "post-" . $cntr; ?>">
        //Post Content
    </li>
<?php $cntr++; ?>
<?php endforeach; ?>

Answer 2

for more details, please post your existing code and explain how you are going to define 'and a specific boxs'.

assuming your post div uses post_class() and you are using the 'standard' loop: in the post div, re-code the post_class(); code, for example:

<?php post_class( ($wp_query->current_post%3 == 2?'different':'') ); ?> 

edited answer - the div with the css class could look like this:

<div class="<?php echo ( ($wp_query->current_post%3 == 2)?'box-last':'box' ); ?>">