Nikita Popov has posted the fourth part of the "PHP's Source Code for PHP Developers" series he and Anthony Ferrara have been posting. In this latest article in the series, Nikita looks specifically at PHP's array implementation and how it's handed "behind the scenes".

Welcome back to the fourth part of the "PHP's Source Code for PHP Developers" series, in which we’ll cover how PHP arrays are internally represented and used throughout the code base.

He starts with an obvious foundation: "everything's a hash table" (even properties, classes and yes, arrays). He describes what a hash table is and talks about two of the most commonly used versions of it in the PHP source - HashTable and Bucket. He gets into their usage a bit and compares this to the corresponding PHP code that uses a standard array.