Question

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How to parse and process HTML with PHP?

$content = "
<p>This is the first paragraph</p>
<p>This is the second paragraph</p>
<p>This is the third paragraph</p>";

Given a string of html content as above, I need to do an insert after the N’th paragraph tag.

How can I parse the content and do an insert of a given string of text, say ‘hello world’ after paragraph 2?

Answer 1

If you are sure about the HTML structure of your string, you can count the seen paragraphs in the callback’s static variable.

$content = preg_replace_callback('#(<p>.*?</p>)#', 'callback_func', $content);

function callback_func($matches)
{
  static $count = 0;
  $ret = $matches[1];
  if (++$count == 2)
    $ret .= "<p> Additional paragraph</p>";
  return $ret;
}

Note that this solution is not reentrant, it is only a concept.