How does PHP memory actually work

Question

I\'ve always heard and searched for new php \'good writing practice\', for example: It\'s better (for performance) to check if array key exists than search in array, but als

Answer 1

Arrays in PHP are implemented as hashmaps. Hence the length of the value you use for the key has little impact on the data requirement. In older versions of PHP there was a significant performance degradation with large arrays as the hash size was fixed at array creation - when collisions starting occurring then increasing numbers of hash values would map to linked lists of values which then had to be further searched (with an O(n) algorithm) instead of a single value, but more recently the hash appears to either use a much larger default size or is resized dynamically (it just works - I can't really be bothered reading the source code).

Saving 4 bytes from your scripts is not going to cause Google any sleepless nights. If you are writing code which uses large arrays (where the savings may be more significant) you're probably doing it wrong - the time and resource taken to fill up the array could be better spent elsewhere (like indexed storage).