PHP - Closing off a div with nested loops - php

Question

I have a folder with around 400 images. I'd like to put them on a page put only eight at a time. Meaning i will have all the images on the same page, but cut in sections of eight images wrapped in a box like this:
<div class="eightbox">
<img src="image1">
<img src="image2">
<img src="image3">
<img src="image4">
<img src="image5">
<img src="image6">
<img src="image7">
<img src="image8">
</div>
<div class="eightbox">
<img src="image9">
<img src="image9">
<img src="image10">
<img src="image11">
<img src="image12">
<img src="image13">
<img src="image14">
<img src="image15">
</div>
Now my code for this so far makes an output, but does not close the "eightbox" so that every new div is inside the other one.
Here's my Code:
<?php
$files = glob("images/*.*"); //loads all the images from my folder into an array
$y = ceil(count($files)/8); // The amount of images divided by eight and rounded up
$z = 1; //This counter makes the array continue outside the loop
for ($i=1; $i<$y; $i++)
{
echo '<div class=\'eightbox\'>';
for ($q=0; $q<8; $q++)
{
$num = $files[$z];
echo '<img src=\'' . $num . '\' >';
$z++;
}
echo '</div>';
}
?>
I hope this makes any sense to you and thanks in advance for helping!
EDIT: on popular demand heres a screenshot of the code i'm getting with chrome:
Screenshot of my code

Answer 1

An alternative which splits the files into chunks of 8 ( using array_chunk()) and then outputs each chunk at a time...
$split = array_chunk($files, 8);
foreach ( $split as $div ) {
echo '<div class=\'eightbox\'>';
foreach ($div as $file ) {
echo '<img src=\'' . $file . '\' />';
}
echo '</div>';
}
Or using implode() to output the data...
$split = array_chunk($files, 8);
foreach ( $split as $div ) {
echo '<div class=\'eightbox\'><img src=\''.
implode('\' /><img src=\'', $div).
'\' /></div>';
}
which IMHO is a little less readable, but more compact.

Answer 2

Using Modulo you could do this
<?php
$files = glob("images/*.*"); //loads all the images from my folder into an array
foreach ( $files as $idx=>$file) {
if ( $idx % 8 == 0 && $idx != 0){ // every 8 close a div and open a new one
echo '</div>';
echo '<div class="eightbox">';
}
if ( $idx == 0 ){ // output first div
echo '<div class="eightbox">';
}
echo "<img src='$file'>";
}
if ( $idx+1 % 8 != 0 ) { // close the last div
echo '</div>';
}
?>