(PHP 4, PHP 5, PHP 7) Sort an array with a user-defined comparison function and maintain index association

(PHP 4, PHP 5, PHP 7) Count all elements in an array, or something in an object

(PHP 5 >= 5.1.0, PHP 7) Computes the difference of arrays using a callback function on the keys for comparison

(PHP 4, PHP 5, PHP 7) Return an array with elements in reverse order

(PHP 4, PHP 5, PHP 7) Sort an array bool sort

(PHP 4, PHP 5, PHP 7) Return the current key and value pair from an array and advance the array cursor

(PHP 4, PHP 5, PHP 7) Return all the keys or a subset of the keys of an array

(PHP 4, PHP 5, PHP 7) Return all the values of an array

(PHP 4 >= 4.2.0, PHP 5, PHP 7) Split an array into chunks

(PHP 4, PHP 5, PHP 7) Fetch a key from an array