Very cool, if true

Oh yeah, I definitely know that isset($array['key']) is faster than in_array($array, 'value')[*], but I couldn't tell you anything specific in big O notation or ratios.

The other advantage of using a keyed array is that you prevent duplicates when you're adding items.


* I can never remember parameter order here, PHP is inconsistent with the order of needle and haystack parameters. Thanks PHP!