Add dynamic classes to an unordered list with PHP - php

Question

I'm trying to add consecutive classes to all list-items in a list with the class of 'nav'. Essentially, I want every list-item to have a class of 'nthChild-x', where x represents its position in the list. I'm a major noob to PHP, so be easy.
Here is the current markup:
<ul id="primaryNav" class="nav">
<li>Blah Blah Uno</li>
<li>Blah Blah Dos</li>
<li>Blah Blah Tres</li>
</ul>
I want this list to be rendered as the following:
<ul id="primaryNav" class="nav">
<li class="nthChild-1">Blah Blah Uno</li>
<li class="nthChild-3">Blah Blah Dos</li>
<li class="nthChild-3">Blah Blah Tres</li>
</ul>
Please don't reply with a JavaScript or JQuery solution. I know how to do this with JS but need this to be server-side. Also, I don't necessarily want to target the ID of the list because I'd rather do it once and target all lists (though that could be a start).
Any ideas?

Answer 1

You can use DOMDocument for that.
This one will work with existing classes and won't add the same class twice.
$dom = new DOMDocument;
$dom->loadHTML($html);
$lists = $dom->getElementsByTagName('ul');
foreach($lists as $list) {
$index = 1;
foreach($list->childNodes as $node) {
if ($node->nodeName != 'li') {
continue;
}
$class = array();
if ($node->hasAttribute('class')) {
$class = preg_split('/\s+/', $node->getAttribute('class'));
}
$addClass = 'nthChild-' . $index;
if (in_array($addClass, $class)) {
continue;
}
$class[] = $addClass;
$node->setAttribute('class', implode(' ', $class));
$index++;
}
}
$html = '';
foreach($dom->getElementsByTagName('body')->item(0)->childNodes as $element) {
$html .= $dom->saveXML($element, LIBXML_NOEMPTYTAG);
}
CodePad.

Answer 2

I suppose you don't use any template system (like Smarty) to generate this. Than you have to use cycle to generate the fields together with integer variable that will have number of iteration stored. It can be done for example like this:
<ul id="primaryNav" class="nav">
<?php
$values = array(1 => "Blah Blah Uno", 2 => "Blah Blah Dos", 3 => "Blah Blah Tres");
for ($i = 1; $i <= 3; $i++) {
echo "<li class=\"nthChild-" . $i . "\">" . $values[$i] . "</li>";
}
?>
</ul>
This solution is quite simple, of course there are many better ways how to do this.

Answer 3

If you only have the list formatted as you've shown here (not in a PHP array), you can do it like this
$markup = '<ul id="primaryNav" class="nav">
<li>Blah Blah Uno</li>
<li>Blah Blah Dos</li>
<li>Blah Blah Tres</li>
</ul>';
if (preg_match_all("/<li>(.*)<\/li>/U",$markup,$result) > 0)
{
$newMarkup = "<ul id=\"primaryNav\" class=\"nav\">\n";
$count = 0;
foreach ($result[1] as $listElement)
{
$count++;
$newMarkup .= "\t<li class=\"nThCild-{$count}\">$listElement</li>\n";
}
print $newMarkup."</ul>\n";
}