Kommentare zu: PHP: Benchmark isset() or array_key_exists() ?

Von: Nik Tang

Nik Tang — Mon, 04 Jul 2011 07:32:51 +0000

I have proposed a method by combining the isset() and array_key_exists() so that its performance is very close to isset() while providing the same result as array_key_exists() does.

If you're interested, just check it out here: http://www.zomeoff.com/php-fast-way-to-determine-a-keyelements-existance-in-an-array/

Von: MFix

MFix — Mon, 25 Apr 2011 19:21:21 +0000

You have written: "But i still do not really know why the cast is so slow".
The answer is pretty simple - not the cast is slow, but error reporting switch is.

Using @ works like:
$tmp = error_reporting();
error_reporting(0);
// do cast
error_reporting($tmp);

Von: nerkn

nerkn — Wed, 04 Aug 2010 07:06:25 +0000

I use to check if the value is usable. Null I know from the mysql definition reads “a missing unknown value”.

If I'm concerning the existance of a value I could surely use isset. If I use keys like an array, the importance is the being there, use array_key_exists is the function.

thanks for benchmarks, I thouht there is huge difference than your results, since one is function, doing many things, and other one is lang construct.

http://dev.mysql.com/doc/refman/5.0/en/working-with-null.html

Von: Julius

Julius — Wed, 19 Aug 2009 20:34:30 +0000

Thats correct Caio.
It also explains why array_key_exists is slower than isset.
But i cant fairly remember a scenairo where i would have needed exactly that behaviour only array_key_exists() has.

I checked documentation, it is mentioned there http://php.net/array_key_exists need to look closer next time :D

Von: Caio

Caio — Wed, 19 Aug 2009 20:00:30 +0000

As I posted on Twitter now, the problem is this: $ php -r '$foo['bar']=NULL;var_dump(isset($foo['bar']));' When value is NULL, isset returns FALSE. But it's set! see?