Question

There are strings in a long text as:

<fn id="T1FN1"> anytext <p> sometext </p> </fn>
<fn id="T2FN1"> anytext <p> sometext </p> </fn>
<fn id="T2FN2"> anytext <p> sometext </p> </fn>
<fn id="F12FN5"> anytext <p> sometext </p> </fn>

etc…

I want to find
<fn </fn> in a text and delete
<p> and </p>
just from these strings, the string between <p> and </p> would not be deleted. I try some preg_replace, but not successful.

Answer 1

You can try using a nested regex:

$html = '<fn id="T1FN1"> anytext <p> sometext </p> </fn>
        <fn id="T2FN1"> anytext <p> sometext </p> </fn>
        <fn id="T2FN2"> anytext <p> sometext </p> </fn>
        <fn id="F12FN5"> anytext <p> sometext </p> </fn>';

preg_replace_callback('/<fn[^>]*>.*?<p>.*?</p>.*?</fn>/', function($matches){
    return preg_replace('/<p>|</p>/', '', $matches[0]);
}, $html);

Note: this syntax requires PHP 5.3+. If you’re running an older version, let me know and I’ll provide the syntax for that.