PHP filter() function - why?
<p>Why would I want to use PHP's <a href="http://www.php.net/filter" rel="nofollow">filter</a> library? Why wouldn't I?</p>

<p>It seems to try and do a bit of clean-up (it's awful when you have to work with regular expressions), but on the other hand function naming and parameter constants seem to be a disaster, if you ask me. It must have been included in PHP for a reason, but I just don't seem to like it. What am I missing?</p>

<p><i>Later edit:</i><br />
Regarding GaryF's answer, I wish to explain a bit why I don't like this function.
This isn't about using it in "my case" if it fits. This is about using it wherever it fits. There's a high chance of needing a filter that won't fit PHP's functions, so I'll have to create my own filter. In that case, the application will use two completely different kinds of functions for data filtering. I consider that to be a much worse practice than just inventing a better wheel.</p>
