How to count foreach loop by range - php

Question

I'm trying to make the carousel slide image slide by 4 images per slide. I want each slide to display four images, and then the next slide will display another four images. I hope I have explained well.
<?php
$i = 0;
foreach ($photos as $photo) {
if ($i == 0) {
?>
<div class="carousel-item active">
<ul class="thumbnails">
<li class="span3">
<div class="thumbnail">
<i class="tag"></i>
<a href="#">
<img src="<?php echo $photo->image_path(); ?>" width="125" height="125" class="img-thumbnail" alt="buy more"/>
</a>
</div>
</li>
</ul>
</div>
<?php
$i++;
} else {
if ($i != 0) {
?>
<div class="carousel-item">
<ul class="thumbnails">
<li class="span3">
<div class="thumbnail">
<i class="tag"></i>
<a href="#">
<img src="<?php echo $photo->image_path(); ?>" width="125" height="125" class="img-thumbnail" alt="buy more"/>
</a>
</div>
</li>
</ul>
</div>
<?php
}
$i++;
}
}
?>

Answer 1

I believe that will do the trick:
<?php
$numImagesPerSlide = 4;
foreach($photos as $k => $photo){
?>
<div class="carousel-item <?php echo ($k % $numImagesPerSlide == 0) ? 'active': '';?>">
<ul class="thumbnails">
<li class="span3">
<div class="thumbnail">
<i class="tag"></i>
<img src="<?php echo $photo->image_path(); ?>" width="125" height="125" class="img-thumbnail" alt="buy more"/>
</div>
</li>
</ul>
</div>
<?php
}
?>
The point is to use $k, whenever it is divisible by 4 (4, 8, 12, 16, ...), with the function $k % $numImagesPerSlide == 0 then you print the code you need.
I guess you will need an extra code, like
if ($k % $numImagesPerSlide == 0) {
//print the header of the carrousel
}