(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) Count all elements in an array, or something in an object

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

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

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

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

(PHP 4 >= 4.0.4, PHP 5, PHP 7) Calculate the sum of values in an array

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

(PHP 4 >= 4.3.0, PHP 5, PHP 7) Computes the difference of arrays with additional index check

(PHP 4, PHP 5, PHP 7) Prepend one or more elements to the beginning of an array