SimpleXMLElement::addAttribute()

(PHP 5 >= 5.1.3, PHP 7)

Adds an attribute to the SimpleXML element

说明

publicSimpleXMLElement::addAttribute(string $name[,string $value[,string $namespace]]): void

Adds an attribute to the SimpleXML element.

参数

$name: The name of the attribute to add.
$value: The value of the attribute.
$namespace: If specified, the namespace to which the attribute belongs.

返回值

没有返回值。

范例

Note:
Listed examples may includeexample.php, which refers to the XML string found in the first example of the basic usage guide.

Example #1 Add attributes and children to a SimpleXML element

<?php
include 'example.php';
 
$sxe = new SimpleXMLElement($xmlstr);
$sxe->addAttribute('type', 'documentary');
$movie = $sxe->addChild('movie');
$movie->addChild('title', 'PHP2: More Parser Stories');
$movie->addChild('plot', 'This is all about the people who make it work.');
$characters = $movie->addChild('characters');
$character  = $characters->addChild('character');
$character->addChild('name', 'Mr. Parser');
$character->addChild('actor', 'John Doe');
$rating = $movie->addChild('rating', '5');
$rating->addAttribute('type', 'stars');
 
echo $sxe->asXML();
?>

以上例程的输出类似于：

<?xml version="1.0" standalone="yes"?>
<movies type="documentary">
 <movie>
  <title>PHP: Behind the Parser</title>
  <characters>
   <character>
    <name>Ms. Coder</name>
    <actor>Onlivia Actora</actor>
   </character>
   <character>
    <name>Mr. Coder</name>
    <actor>El Act&#xD3;r</actor>
   </character>
  </characters>
  <plot>
   So, this language. It's like, a programming language. Or is it a
   scripting language? All is revealed in this thrilling horror spoof
   of a documentary.
  </plot>
  <great-lines>
   <line>PHP solves all my web problems</line>
  </great-lines>
  <rating type="thumbs">7</rating>
  <rating type="stars">5</rating>
 </movie>
 <movie>
  <title>PHP2: More Parser Stories</title>
  <plot>This is all about the people who make it work.</plot>
  <characters>
   <character>
    <name>Mr. Parser</name>
    <actor>John Doe</actor>
   </character>
  </characters>
  <rating type="stars">5</rating>
 </movie>
</movies>

参见

SimpleXMLElement::addChild() Adds a child element to the XML node
Basic SimpleXML usage

You cannot use this to update an existing attribute's value.
Instead, get a DOM version of the SimpleXMLElement and use setAttribute, as per:
$XML = '<element a="aa">Text</element>';
$snode = new simple_xml_element($XML);
$dnode = dom_import_simplexml($snode);
$dnode->setAttribute('a', 'bb');
Resulting XML for the node is:
<element a="bb">Text</element>

If the attribute already exists, addAttribute does nothing.
example:
<?php
$xml_string = <<<XML
<?xml version="1.0" encoding="UTF-8"?>
<root>
  <item id="foo">
<root>
XML;
$xml = simplexml_load_string($xml_string);
$xml->item->addAttribute('id', 'bar');
echo $xml->asXML();
?>
The above examples will output:
<?xml version="1.0" encoding="UTF-8"?>
<root>
  <item id="foo">
<root>

If you need an Namespace, you must write a Prefix of the Namespace + the Name of the Attribute ("prefix:name") as the first parameter AND the uri as the third one. (I don't know why?!)
Example code:
<?php
$xml = new SimpleXMLElement("<packagedElement></packagedElement>");
$xml->addAttribute("xmi:type", "uml:Class", "http://schema.omg.org/spec/XMI/2.1"); 
echo $xml->asXml();
?>
Output:
<packagedElement xmlns:xmi="http://schema.omg.org/spec/XMI/2.1" xmi:type="uml:Class"></packagedElement>

You can access a node child with his name this way :
<?php
$root = new SimpleXMLElement($filePath);
echo $root->nodeName->attributes;
// It works recursivly so this will work too
echo $root->nodeName->subNodeName->attributes();
?>
But if you want to ADD an attribute to a children you MUST use the children() method to access and modfiy it or it will modify the parent's attributes.
<?php
// Add a subnode
$element->nodeName->addChild('subNodeName', "whatever you want");
        
// Get the pos in the childrens of the parent node
$lastNodePos = $element->nodeName->count() 1;
// Get the parents node childrens
$nodeChildrens = $element->nodeName->children();
// Add an attribute to the last created
$nodeChildrens[$lastNodePos]->addAttribute('attributeName', "The attribute value);
?>