I just wanted to give this site I stumbled upon some credit: http://www.hackingwithphp.com/. I’ve been developing with PHP for about 15 years, but still the part about performance taught me quite a lot. isset() is apparently faster than array_key_exists() and $i++is slow compared to ++$i. These are micro-optimizations, sure, but there’s no reason to rub PHP the wrong way…
/Peder