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I have the following stored in a MySQL table:

<p>First paragraph</p><p>Second paragraph</p><p>Third paragraph</p><div class="item"><p>Some paragraph here</p><p><strong><u>Specs</u>:</strong><br /><br /><strong>Weight:</strong> 10kg<br /><br /><strong>LxWxH:</strong> 5mx1mx40cm</p><p>This is the paragraph I am trying to remove with regex.</p></div>

I'm trying to remove the last paragraph tags and content on every row in the table. I can loop through the table with PHP easily enough, but the regex has me stumped.

Every preg_match I've found on stackoverflow either gives me a "preg_match(): Unknown modifier" error, or the var_dump shows an empty array. I believe that would only match the content even if it did work so I think I need preg_replace?

The rows aren't identical in length, but it is always going to be the last paragraph that I want to completely remove.

Would appreciate if someone could show me how. Thanks

Andy Lester
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Will
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  • What is the regex(s) you have? `Unknown modifier` usually means you aren't using delimiters or you are using your delimiter in your expression unescaped. – chris85 Jun 19 '15 at 02:05
  • Well the one I have currently is:- preg_match('/

    ([^<]*)<\/p>$/', $description, $matches); var_dump($matches); - This just gives me an empty array.

     – Will Jun 19 '15 at 02:16
  • That `$` is looking for the end of the string, not your targeted ending. I'll write something up that should be able to handle this. You should look into using an HTML/XML parser in the future, this can get messy very quickly. – chris85 Jun 19 '15 at 02:18

2 Answers2

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This would remove the last <p>anything</p>.

<?php
$html = '<p>First paragraph</p><p>Second paragraph</p><p>Third paragraph</p><div class="item"><p>Some paragraph here</p><p><strong><u>Specs</u>:</strong><br /><br /><strong>Weight:</strong> 10kg<br /><br /><strong>LxWxH:</strong> 5mx1mx40cm</p><p>This is the paragraph I am trying to remove with regex.</p></div>';
$html = preg_replace('~(.*)<p>.*?</p>~', '$1', $html);
echo $html;

The (.*) is grabbing everything until the last paragraph tag and storing it. The .*? grabs everything between the paragraph tags, the ? tells it to stop at the next closing paragraph tag. We don't use the capturing here because we don't care what is inside. The $1 is the found content before the last <p>. The ~ are delimiters telling where the regex begins and ends. I suspect this is what is causing your regexs to fail currently. http://php.net/manual/en/regexp.reference.delimiters.php

Output:

<p>First paragraph</p><p>Second paragraph</p><p>Third paragraph</p><div class="item"><p>Some paragraph here</p><p><strong><u>Specs</u>:</strong><br /><br /><strong>Weight:</strong> 10kg<br /><br /><strong>LxWxH:</strong> 5mx1mx40cm</p></div>

Note: There are XML/HTML parsers you should consider using them because regexs with HTML/XML can get very messy quickly.

http://php.net/manual/en/refs.xml.php
How do you parse and process HTML/XML in PHP?

Demo: http://sandbox.onlinephpfunctions.com/code/0ddf46c328323e8b6357313a5464733ff797bc3f

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chris85
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  • Good point. And if the HTML contains things like it can throw off regex as well. – Ben P. Dorsi-Todaro Jun 19 '15 at 02:22
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    Thanks, this worked perfect. I'll take a look at XML parsers as I think this kind of problem will crop up again in this project. An old database with tons of HTML stored in it :( – Will Jun 19 '15 at 02:23
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A solution without regexp would be

$string = '<p>First paragraph</p><p>Second paragraph</p><p>Third paragraph</p><div 
class="item"><p>Some paragraph here</p><p><strong><u>Specs</u>:</strong><br /><br /> 
<strong>Weight:</strong> 10kg<br /><br /><strong>LxWxH:</strong> 5mx1mx40cm</p><p>This 
is the paragraph I am trying to remove with regex.</p></div>';

$lastOccurenceOfEnd = strrpos($string,"</p>");
$lastOccurenceOfStart = strrpos($string,"<p>");
$removedParagraph = substr_replace($string, '', $lastOccurenceOfStart, 
$lastOccurenceOfEnd-$lastOccurenceOfStart+4);

echo $removedParagraph;
Alexandru Corlan
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