SunshinePHP Developer Conference 2015

SimpleXMLElement::xpath

(PHP 5 >= 5.2.0)

SimpleXMLElement::xpathRuns XPath query on XML data

Descrierea

public array SimpleXMLElement::xpath ( string $path )

The xpath method searches the SimpleXML node for children matching the XPath path.

Parametri

path

An XPath path

Valorile întoarse

Returns an array of SimpleXMLElement objects or FALSE in case of an error.

Exemple

Example #1 Xpath

<?php
$string 
= <<<XML
<a>
 <b>
  <c>text</c>
  <c>stuff</c>
 </b>
 <d>
  <c>code</c>
 </d>
</a>
XML;

$xml = new SimpleXMLElement($string);

/* Search for <a><b><c> */
$result $xml->xpath('/a/b/c');

while(list( , 
$node) = each($result)) {
    echo 
'/a/b/c: ',$node,"\n";
}

/* Relative paths also work... */
$result $xml->xpath('b/c');

while(list( , 
$node) = each($result)) {
    echo 
'b/c: ',$node,"\n";
}
?>

Exemplul de mai sus va afișa:

/a/b/c: text
/a/b/c: stuff
b/c: text
b/c: stuff

Notice that the two results are equal.

Vedeți de asemenea

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User Contributed Notes 14 notes

up
6
drewish at katherinehouse dot com
9 years ago
xpath() can also be used to select elements by their attributes. For a good XPath reference check out: http://www.w3schools.com/xpath/xpath_syntax.asp

<?php
$string
= <<<XML
<sizes>
    <size label="Square" width="75" height="75" />
    <size label="Thumbnail" width="100" height="62" />
    <size label="Small" width="112" height="69" />
    <size label="Large" width="112" height="69" />
</sizes>
XML;

$xml = simplexml_load_string($string);
$result = $xml->xpath("//size[@label='Large']");

// print the first (and only) member of the array
echo $result[0]->asXml();
?>

The script would print:
<size label="Large" width="112" height="69"/>
up
9
grummfy at gmail dot com
4 years ago
On a xml that have namespace you need to do this before your xpath request (or empty array will be return) :

<?php
$string
= str_replace('xmlns=', 'ns=', $string); //$string is a string that contains xml...
?>
up
3
yetihehe at yetihehe dot com
3 years ago
Xpath actually knows which element is root regardless of element on which you execute it. Example:

<?php

$string
= <<<XML
<a>
<b>
  <c>text</c>
  <c>stuff</c>
</b>
<b>
  <c>code</c>
</b>
</a>
XML;

header('content-type: text/plain');

$xml = new SimpleXMLElement($string);

//relative to root
$b0=$xml->b[0]->xpath('//c');
while(list( ,
$node) = each($b0)) {
    echo
'b[0]: //c: ',$node,"\n";
}

$b1=$xml->b[1]->xpath('//c');
while(list( ,
$node) = each($b1)) {
    echo
'b[1]: //c: ',$node,"\n";
}

echo
"\n";

//relative to current element
$b0=$xml->b[0]->xpath('.//c');
while(list( ,
$node) = each($b0)) {
    echo
'b[0]: .//c: ',$node,"\n";
}

$b1=$xml->b[1]->xpath('.//c');
while(list( ,
$node) = each($b1)) {
    echo
'b[1]: .//c: ',$node,"\n";
}

?>

Will return:
b[0]: //c: text
b[0]: //c: stuff
b[0]: //c: code
b[1]: //c: text
b[1]: //c: stuff
b[1]: //c: code

b[0]: .//c: text
b[0]: .//c: stuff
b[1]: .//c: code
up
4
canuemail at gmail dot com
6 years ago
If you want to search multiple values from xml on the behalf or one value then this code can be helpfull to you.

if there is:
<Record>
  <country>Pakistan</country>
  <code>+92</code>
  <Value>100<Value>
</Record>

then try this one:
<?php
$sxe
simplexml_load_file("countries.XML");
foreach(
$sxe->xpath('//RECORD') as $item) {

   
$row = simplexml_load_string($item->asXML());
   
$v = $row->xpath('//country[. ="Pakistan"]');
    if(
$v[0]){
        print
$item->country;
        print
$item->code;
        print
$item->value;
    }
   
}
?>
up
3
anemik
6 years ago
If you want to find easly all records satisfying some condition in XML data like

....
   <book id="bk101">
      <author>Gambardella, Matthew</author>
      <title>XML Developer's Guide</title>
      <genre>Computer</genre>
      <price>44.95</price>
   </book>
   <book id="bk102">
      <author>Ralls, Kim</author>
      <title>Midnight Rain</title>
      <genre>Fantasy</genre>
      <price>5.95</price>
   </book>
...

try example below

<?php

$xmlStr
= file_get_contents('data/books.xml');
$xml = new SimpleXMLElement($xmlStr);
// seach records by tag value:
// find all book records with price higher than 40$
$res = $xml->xpath("book/price[.>'40']/parent::*");
print_r($res);

?>

You will see response like:
Array (
[0] => SimpleXMLElement Object
        (
            [@attributes] => Array
                (
                    [id] => bk101
                )

            [author] => Gambardella, Matthew
            [title] => XML Developer's Guide
            [genre] => Computer
            [price] => 44.95
            [publish_date] => 2000-10-01
            [description] => An in-depth look at creating applications
      with XML.
        )
...
up
1
Hugh
8 years ago
Note that this function does not ALWAYS return an array. It seems that if the specified path is not found in the document, it will return false. You need to check for the false value before using foreach, if you wish to avoid a warning (and often to handle errors or control program flow in this situation).
up
0
leonjanzen at gmail dot com
2 days ago
To run an xpath query on an XML document that has a namespace, the namespace must be registered with SimpleXMLElement::registerXPathNamespace() before running the query. If the XML document namespace does not include a prefix, you must make up an arbitrary one, and then use it in your query.

<?php
$strXml
= <<<XML
<?xml version="1.0" encoding="UTF-8"?>
<mydoc xmlns="http://www.url.com/myns">
    <message>Test message</message>
</mydoc>
XML;

$xmlDoc=new \SimpleXMLElement($strXml);

foreach(
$xmlDoc->getDocNamespaces() as $strPrefix => $strNamespace) {
    if(
strlen($strPrefix)==0) {
       
$strPrefix="a"; //Assign an arbitrary namespace prefix.
   
}
   
$xmlDoc->registerXPathNamespace($strPrefix,$strNamespace);
}

print(
$xmlDoc->xpath("//a:message")[0]); //Use the arbitrary namespace prefix in the query.
?>

This will output:

Test message
up
0
BenjaminBeck at gmx dot de
1 month ago
If you want to search multiple values from xml on the behalf or one value then this code can be helpfull to you.

if there is:
<Record>
  <country>Pakistan</country>
  <code>+92</code>
  <Value>100<Value>
</Record>

then try this one:
<?php
$sxe
simplexml_load_file("countries.XML");
foreach(
$sxe->xpath('//RECORD') as $item) {

   
$v = $row->xpath('./country[. ="Pakistan"]');
    if(
$v[0]){
        print
$item->country;
        print
$item->code;
        print
$item->value;
    }
   
}
?>
up
0
stefan at efectos dot nl
3 years ago
Having problems selecting information through xpath when there are namespaces in the XML?

Try this quick and dirty solution, but it works:

<?php
$objImageXml
= new SimpleXMLElement($objImageXml->asXML());
?>
up
0
behnam@zwnj
5 years ago
Seems like this function cannot return the result of XPath string() [1] function.  For example if you query xpath("string(a/@b)") you will get bool(false) although the node "a" may have the attribute "b" set to a non-empty string.

[1] http://www.w3.org/TR/xpath#section-String-Functions
up
0
paul at pmtlogic dot com
6 years ago
xpath doesn't seem to be able to handle single quotes embedded in the query itself. For instance, I want to find geo coordinates in an xml file based on country name.

xml snippet:

<zones>
<zone country="Cote d'Ivoire" fullName="Yamoussoukro" geo="6.82,-5.28" id="1050"><url prefix="1001" value="fiji.html" /><url prefix="1002" value="C" /></zone>
</zones>

The following code does not work:

<?php
$xml
= simplexml_load_file("my.xml");
$result = $xml->xpath("//zone[@country='Cote d\'Ivoire']");

foreach (
$result[0]->attributes() as $key => $val ) {
    print
"<div class='coords'>$key: $val</div>\n";
}
?>

I have tried many variations on the embedded single quote (i.e. escape codes) but with no result. W3C offers no explanation either.

In addition, there doesn't seem to be any way of embedding wildcards in the attribute value (you can embed wildcards in the attribute name). Otherwise the following might be a reasonable substitute in this context:

<?php $result = $xml->xpath("//zone[@country='Cote d*Ivoire']"); ?>
up
-1
DrupalFocus at earthlink dot net
4 years ago
Looks like the relative path is relative to the SimpleXMLElement object that you call the Xpath() method on.  Basically chopping off the root element.

<?php
$string
= <<<XML
<foo>
  <bar>
    <a>
     <b>
      <c>text</c>
      <c>stuff</c>
     </b>
     <d>
      <c>code</c>
     </d>
    </a>
  </bar>
</foo>
XML;

$xml = new SimpleXMLElement($string);
/* Search for children using 2nds level relative <bar><a><b><c> */
$result = $xml->xpath('a/b/c');
if (
$result)
foreach(
$result as $node) {
   
drupal_set_message(t('a/b/c: @node.', array('@node' => $node)));
}
else
 
drupal_set_message(t('a/b/c: failed.'));
                    
/* it relative to the SimpleXMLElement Search for 2nds level relative <bar><a><b><c> but where is foo */
$bar = $xml->bar;
$result = $bar->xpath('a/b/c');
foreach(
$result as $node) {
   
drupal_set_message(t('bar->a/b/c: @node.', array('@node' => $node)));
}
?>

results in :
#
# a/b/c: failed.
# bar->a/b/c: text.
# bar->a/b/c: stuff.
up
-1
arealzone-czernobyl at yahoo dot de
5 years ago
The simplest way to count nodes in a XML doc:

<?php
$xml
= new SimpleXMLElement($xmlstr);

$xmlNode = $xml->xpath('root/yourNodeName');
$nodeCount = count($xmlNode);

echo
$nodeCount;
?>
up
-3
Anti Veeranna
5 years ago
Whether it returns a false or empty array for a non-existing path seems to depend on libxml version.

I tried the following code:

<?php
$data
= '<foo><bar></bar></foo>';
$xml = simplexml_load_string($data);
print
gettype($xml->xpath('/first/second'));
?>

On a machine with libxml 2.6.16 and PHP 5.2.8 I got back boolean. On a different machine with libxml 2.7.3 and PHP 5.2.8/5.2.9 I got back empty array.

You can check the libxml version from command line by executing: php --ri libxml

or simply look at phpinfo() output
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