(PHP 5 >= 5.3.0, PHP 7) Serialize an ArrayObject

(PHP 5 >= 5.1.0, PHP 7) Gets the behavior flags.

(PHP 5 >= 5.2.0, PHP 7) Sort the entries with a user-defined comparison function and maintain key association

(PHP 5 >= 5.0.0, PHP 7) Returns the value at the specified index

(PHP 5 >= 5.1.0, PHP 7) Gets the iterator classname for the ArrayObject.

(PHP 5 >= 5.2.0, PHP 7) Sort entries using a "natural order" algorithm

(PHP 5 >= 5.0.0, PHP 7) Appends the value

(PHP 5 >= 5.2.0, PHP 7) Sort the entries by value

(PHP 5 >= 5.0.0, PHP 7) Sets the value at the specified index to newval

(PHP 5 >= 5.1.0, PHP 7) Exchange the array for another one.