How PHP uses xpath to parse XML

This article mainly introduces the method of PHP using xpath to parse XML. It analyzes the Xpath syntax in detail with examples, as well as the operation steps and related implementation skills of parsing xml documents through Xpath. Friends in need can refer to it

The example in this article describes how PHP uses xpath to parse XML. Share it with everyone for your reference, the details are as follows:

XML files are widely used in lightweight applications developed by PHP websites, and there are many ways for PHP to parse and read XML files, such as JS DOM, XML files are parsed using SimpleXml,

What is Xpath?

Xapth is mainly used to query information in XML documents. It can parse XML files and read data in XML files by using path expressions.

Recommended tutorial for PHP parsing XML: How to parse XML documents under PHP4 and PHP5 versions

XML documents that require PHP parsing:

<?xmlversion="1.0"encoding="gbk"?>
<LeapsoulXML> 
<LeapsoulInfo> 
<name>PHP网站开发-PHP教程-jb51.net</name>
  <website>http://www.jb51.net</website>
 </LeapsoulInfo>
 <LeapsoulInfo> 
<name>
   <keywords>
   <keywordkeyid=&#39;1&#39;>PHP网站开发</keyword>
   <keywordkeyid=&#39;2&#39;>PHP教程</keyword>
   <keywordkeyid=&#39;3&#39;>PHP</keyword>
   </keywords>
   <seo>SEO</seo>
  </name>
 </LeapsoulInfo>
 <WebInfo> 
<name>PHP网站开发</name>
  <website>http://www.jb51.net</website>
 </WebInfo>
</LeapsoulXML>

Xpath syntax tutorial

/ represents from The root node in the XML file starts to be parsed
//Indicates matching the selected current node in the XML file without considering its positional relationship (similar to fuzzy query in SQL)
. Indicates selecting the current node
..Indicates selecting the parent node of the current node
@Indicates matching a specific node or attribute

The first step of PHP parsing XML instance

$xml = simplexml_load_file('leapsoulcn.xml');

Instructions: Use PHP SimpleXML to load the XML document that needs to be parsed. SimpleXML is supported by PHP5 by default.

Example 1:

foreach($xml->xpath('LeapsoulInfo')as $value) { 
  print_r($value);
}

Description: In this Xpath instance, query the specified node through Xpath in the form of an array Return all its child nodes and print out the final array structure through PHP's print_r function.

Example 2:

foreach($xml->xpath('LeapsoulInfo/name')as $value) { 
  print_r($value);
}

Explanation: In this Xpath instance, specify the needs through the Xpath path expression Xapth queries a specific child node and returns the elements of this child node in the form of an array.

Example 3:

foreach($xml->xpath('//name')as $value) { 
  print_r($value);
}

Description: In this Xpath instance, // is used to query XML using Xpath The difference between all name node elements in the file and the previous Xpath instance is that name has no positional relationship.

Example 4:

foreach($xml->xpath('LeapsoulInfo//name')as $value) { 
  print_r($value);
}

Description: PHP parses a child node under the specified node in the XML file to Returns all its child nodes in array form, ignoring the positional relationship of the specified child node in LeapsoulInfoXML.

Example 5:

foreach($xml->xpath("//name/keywords/keyword[@keyid='1']")as $value) { 
  print_r($value);
}

##Instructions: In the XML file that needs to be parsed by PHP Find the element with keyid=1 through Xpath and return it in array form.

OK, the above-mentioned PHP Xpath example tutorials are the most basic methods for PHP to parse XML files. By rationally using Xpath path expressions, you can perform complex XML query and parsing, and it feels as convenient to use as SQL.

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