Converting Between SimpleXML and DOM Objects
Using SimpleXML is usually easier than using DOM, but sometimes DOMâs comprehensiveness lets you do something thatâs either hard or impossible in SimpleXML.
For example, you cannot discover the name of the root element in SimpleXML, but thatâs no problem in DOM, as shown in Example 5-3.
Example 5-3. Converting between SimpleXML and DOM objects
$ab = simplexml_load_file('address-book.xml');
// Find the name of the root node
$name = dom_import_simplexml($ab)->tagName;
print $name;
address-book
SimpleXML gobbles up the root element, so thereâs no
way to derive its name using SimpleXML. However, the
dom_import_simplexml( )
function takes a SimpleXML object and converts it to a
DOM document. Under DOM, reference the objectâs
tagName
property and youâre done.
These conversion features are particularly useful when youâre using SimpleXML as a generic XML document parser, because SimpleXML doesnât really support XML document introspection. In contrast, DOM excels at this task.
Alternatively, you can perform the reverse transformation, as shown in Example 5-4.
Example 5-4. Converting between DOM and SimpleXML objects
$ab = new DOMDocument;
$ab->load('address-book.xml');
// Find the email address of the first person
$email = simplexml_import_dom($ab)->person->email;
print $email;
rasmus@php.net
Use the
simplexml_import_dom( )
function to turn a DOM object into a SimpleXML object.
Donât worry about the performance overhead of these ...
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