foreach() every 4 change output - php

Question

I have an issue where I don't know for a foreach() loop to change the output on every(x) amount of results.
Here is my foreach() code:
$dir_handle = 'assets/icons/';
foreach(array_diff(scandir($dir_handle), array('.', '..')) as $file) {
$cut = substr($file, -4);
echo '<img id="preload_header" src="assets/icons/' . $file . '" /><br />';
}
How would I get it for that 1-4 have the same result, but then 5-8 have a different result, and then back to 1-4?

Answer 1

You want to do a count in your foreach loop
$count = 1;
foreach(array_diff(scandir($dir_handle), array('.', '..')) as $file) {
//Check if count is between 1 and 4
if($count >= 1 && $count <= 4) {
//Do something
} else { //Otherwise it must be between 5 and 8
//Do something else
//If we are at 8 go back to one otherwise just increase the count by 1
if($count == 8) {
$count = 1;
} else {
$count++;
}
}
}

Answer 2

You can use the % operator, combined with a division by 4:
foreach ($a as $key => $val) {
$phase = $key / 4 % 2;
if ($phase === 0) {
echo 'here';
}
elseif ($phase === 1) {
echo 'there';
}
}
This switches between the two branches every 4 iterations of your loop.
As pointed out in the comments, the above method assumes that the keys of your array are in order. If not, you can add a counter variable in the loop, like:
$c = 0;
foreach ($a as $val) {
$phase = $c++ / 4 % 2;
if ($phase === 0) {
echo 'here';
}
elseif ($phase === 1) {
echo 'there';
}
}