(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 all the keys or a subset of the keys of an array

(PHP 4, PHP 5, PHP 7) Creates a PHP value from a stored representation

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

(PHP 4 >= 4.0.5, PHP 5, PHP 7) Searches the array for a given value and returns the corresponding key if

(PHP 7) Checks if it is a built-in type public

(PHP 4, PHP 5, PHP 7) Finds whether a variable is an object

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

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

(PHP 5 >= 5.1.0, PHP 7) Invokes function args