(PHP 5 >= 5.2.0, PHP 7) Sets the regular expression flags.

(PHP 5 >= 5.1.0, PHP 7) Rewind the iterator to the specified starting offset

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

(PHP 5 >= 5.1.0, PHP 7) Return the inner iterator's children contained in a RecursiveFilterIterator

(PHP 5 >= 5.1.0, PHP 7) Get current element