How to increment $var value without a loop in PHP? - php

Question

I have this issue where i want to increase a value with 1 and apply this to my HTML, but i can't use a for() or while() loop (at least i think i can't). I'm customizing an e-merchandise program (opencart) and my php knowledge isn't enough to tackle the problem.
There is this function which displays the categories from the store. It uses a variable that is constantly updated via $var .= "value".
I'm so far that i know how many sub-categories there are, but i don't know how to apply this range to my HTML.
I'm working towards a situation like below
<ul id="cats">
<li id="cat1">Cat
<ul id="sub1">
<li>item</li>
<li>item</li>
</ul>
</li>
<li id="cat2">Cat
<ul id="sub2">
<li>item</li>
<li>item</li>
</ul>
</li>
</ul>
I don't have a clue how to increase the count of the second unordered lists. Below the code where the second unordered lists are generated.
[..]
$cPiD = strlen($parent_id);
if ($results) {
if ($parent_id == 0) {
$output .= '<ul id="cats">';
} else {
$output .= '<ul id="sub'.$cPiD.'">';
}
}
[..]
The variable $cPiD holds the total amount of sub categories (in this case 2). I want this variable to automatically apply the correct number to the unordered list (so apply id="sub1" to the first unordered list and id="sub2" tot he second one (as in my example above)).
The problem is that i can't use a for() loop after the else part, because in my HTML i wil get two <ul> tags instead of one.
Below the PHP code where it all happens
$category_id = array_shift($this->path);
$output = '';
$results = $this->model_catalog_category->getCategories($parent_id);
$count = 0;
$cPiD = strlen($parent_id);
if ($results) {
if ($parent_id == 0) {
$output .= '<ul id="cats">';
} else {
$output .= '<ul id="sub'.$cPiD.'">';
}
}
foreach ($results as $result) {
$count++;
if (!$current_path) {
$new_path = $result['category_id'];
$output .= '<li id="cat'.$count.'">';
} else {
$new_path = $current_path . '_' . $result['category_id'];
$output .= '<li>';
}
$children = '';
$children = $this->getCategories($result['category_id'], $new_path);
$output .= $result['name'];
$output .= $children;
if (!$current_path) {
$output .= '</li>';
} else {
$output .= '</li>';
}
}
if ($results) {
if ($parent_id == 0) {
$output .= '</ul>';
} else {
$output .= '</ul>';
}
}
Does anybody maybe have an idea how to solve this?
EDIT:
Oh, i tries adding the following construction in the foreach() loop, but that gave problems when a certain categories don't have any sub categories.
if (!$current_path) {
$output .= '$result['name'] . ' <ul id="sub'.$count.'">';
}else{
$output .= $result['name'];
}

Answer 1

You can use this:
// at the top of your code (ouside of the loop)
$cPiD = 1;
// inside the loop you need to increment the parameter
$output .= '<ul id="sub'.$cPiD++.'">';
After each time the item is used, its value will be incremented by 1. (after already using it)