Question

In $var there is some code. I’m trying to operate a nl2br() on text inside each <p></p>.

echo preg_replace('/<p>(.*?)</p>/i', nl2br('${1}'), $var);

This code doesn’t work.

How do I fix this?

Answer 1

It looks like preg_replace_callback might be what you’re looking for: https://www.php.net/manual/en/function.preg-replace-callback.php

ETA: In your specific example, you could either use an anonymous function (only if you’re doing this once or twice, otherwise it eats up memory) or define a helper function

function nl2br_wrapper($matches)
{
    return "<p>".nl2br($matches[1])."</p>";
}

preg_replace_callback('/<p>(.*?)<\/p>/si', "nl2br_wrapper", $var);