The SimpleXML iterator allows you to use SimpleXML objects with the other iterator classes. This allows you to easily construct an SQL-like interface to XML files.
For instance, suppose you have an XML address book like the one in Example 5-1. However, instead of containing only 2 records, it contains hundreds of records, and you want to display the records in groups of 10.
One solution is to place the information into a database. Another is to use XPath. A third is to combine a SimpleXMLIterator with a LimitIterator:
$ab = file_get_contents('address-book.xml'); $page = 0; $limit = 10; foreach (new LimitIterator(new SimpleXMLIterator($ab), $page * $limit, $limit) as $person) { print "$person->firstname $person->lastname: $person->email\n"; }
The SimpleXMLIterator takes a string of XML and creates an iterable SimpleXML object. Here, it's parsing address-book.xml.
This iterator is then passed to a LimitIterator that restricts the output to only the $limit number of records beginning at $page * $limit. When $page is 0, it returns the first 10 records; when $page is 1, you get records 11 through 20.
The $person item can be treated like a SimpleXMLElement, so $person->firstname returns the text stored in the firstname element.