(PHP 5 >= 5.1.2, PHP 7) Sets the class used with

(PHP 5 >= 5.1.0, PHP 7) Set behaviour flags

(PHP 5 >= 5.3.0, PHP 7) Compare elements in order to place them correctly in the heap while sifting up.

(PHP 5 >= 5.3.0, PHP 7) Check whether the array contains more elements

(PHP 5 >= 5.2.0, PHP 7) The offsetUnset purpose

(PHP 5 >= 5.0.0, PHP 7) Check whether array contains more entries

(PHP 5 >= 5.3.0, PHP 7) Unsets the value at the specified $index

(PHP 5 >= 5.3.0, PHP 7) Return current array index

(PHP 5 >= 5.3.0, PHP 7) Move to next entry

(PHP 5 >= 5.1.0, PHP 7) The rewind() method