It was an associative array all along, PHP just hides that from you. The Array is such a quirky data structure, it takes int or string keys, but numeric string

It was an associative array all along, PHP just hides that from you. The Array is such a quirky data structure, it takes int or string keys, but numeric string keys ("1", etc.) are silently converted to int. It's never a real array, the implementation under the hood is a hash table.