Inserting numerical ID's in paragraphs (PHP/MySQL DB Query) - php

Question

I have a pretty ordinary query that displays articles stored in a database table (field = 'Article')...
while ($row = $stm->fetch())
{
$Content = $row['Article'];
}
echo $Content;
I'd like to know how I can modify the display so that every paragraph has a numerical ID. For example, the first paragraph would be [p id="1"], the second one [p id="2"] and so on. However, it would be even better if the last paragraph displayed as [p id="Last"].
(Sorry, I forgot how to post inline code, so I replaced the tags (e.g. <) with brackets.)
My goal is to simply get more control over my content. For example, there are certain items that I want to include after the first paragraph on some pages, and I might want to include a certain feature before paragraph#4 on one special page.
ON EDIT... Neither of the methods suggested below worked for me, but it' probably because I simply didn't implement them correctly; the code in both examples isn't familiar to me. At any rate, I'm bookmarking this page so I can learn more about those scripts.
In the meantime, I finally found a regex solution. (I think preg_replace is another word for regex, right?)
This inserts a numerical ID in each paragraph tag:
$c = 1;
$r = preg_replace('/(<p( [^>]+)?>)/ie', '"<p\2 id=\"" . $c++ . "\">"', $Article);
$Article = $r;
This changes the ID in the last paragraph tag to "Last"...
$c = 1;
$r = preg_replace('/(<p( [^>]+)?>)/ie', '"<p\2 id=\"" . $c++ . "\">"', $Article);
$r = preg_replace('/(<p.*?)id="'.($c-1).'"(>)/i', '\1id="Last"\2', $r);
$Article = $r;

Answer 1

Assuming your HTML is well-formed, you could use the SimpleXMLElement class to do so:
$sxe = new SimpleXMLElement($row['Article']);
$i = 0;
foreach ($sxe->children() as $p) {
$p->addAttribute('id', $i);
}
$p->id = 'Last'; // to set the ID of the last paragraph
echo $sxe->__toString();
If it isn't well-formed, you could use the DOMDocument class instead:
$dom = new DOMDocument;
$dom->loadHTML($row['Article']);
$i;
foreach ($dom->getElementsByTagName('p') as $p) {
$p->id = $id;
}
$p->id = 'Last';
echo $dom->saveHTML();