Hello folks. I've been familiar with PHP for quite a while now and consider myself to be a higher-level intermediate PHP script writer; however, I'd like to learn more... sometimes there are neat things in scripts that other people have written, and I can usually search to find out how it works so that I can learn. I'm stuck here though...

$selected = is_null($selected) ? date('Y') : $selected;

I have searched and searched for an explanation of the above line, but I cannot find it.

Also, can anybody inform me as to the location on the internet where I might find an in-depth explanation on the preg_match, and alike, functions? I've looked at the PHP.net information, and I understand what the function does, but it doesn't go into in-depth detail as to how to use the different symbols in order to narrow the filter.

I think that's it for now.