PHP self-learning path-XML programming (DOM technology)

Source: Internet
Author: User
Document directory
  • 4. Delete Elements
In the previous section, we talked about the basic syntax and elements, entity and DTD constraints of XML files. Next we will officially enter the XML programming of PHP to operate XML files using PHP Technology.
There are three common technologies:
1. php dom
2. php uses XPath to operate XML
3. simplexml Technology
First, describe dom
The core idea of dom (Document Object Model) Document-object-model is to regard an XML file as an object model and then operate XML files through objects.
1. When creating an XML file, you can find that the XML file directly compiled by you cannot be correctly identified when calling the XML function, therefore, create an XML file using PHP and then perform operations to view the Code directly.
<? PHP // instantiate a domdocument object $ dom = new domdocument ('1. 0', 'utf-8'); // create an IF (! File_exists ("xml_test.xml") {header ("Content-Type: text/plain"); $ root = $ dom-> createelement ("class "); $ dom-> appendchild ($ root); $ dom-> Save ("xml_test.xml");} else {$ dom-> load ("xml_test.xml ");} print $ dom-> savexml ();?>
Open on the webpage and execute the command to create an xml_test.xml file (the problem here is that the root directory name cannot use Chinese characters, but I don't know how to set it? Thank you very much for your advice !)
<?xml version="1.0" encoding="UTF-8"?><class/>
2. Add Elements
<? PHP // addelementsxml. PHP $ dom = new domdocument ("1.0", "UTF-8"); $ dom-> load ("xml_test.xml "); $ root_class = $ dom-> getelementsbytagname ("class"); $ I = 0; // For ($ I = 0; $ I <4; $ I ++) {$ root_class_node = $ root_class-> item ($ I); $ stu_node = $ dom-> createelement ("student"); $ stu_node-> setattribute ("xingbie ", "Man"); $ stu_node_name = $ dom-> createelement ("name", "name ". $ I); // set the attribute $ stu_node_name-> setattribute ("He L "," 23 "); $ stu_node_age = $ dom-> createelement (" Age "," 21 "); $ stu_node_introduce = $ dom-> createelement (" introduce ", "1111"); $ stu_node-> appendchild ($ stu_node_name); $ stu_node-> appendchild ($ stu_node_age); $ stu_node-> appendchild ($ stu_node_introduce ); $ root_class_node-> appendchild ($ stu_node); //} $ dom-> Save ("xml_test.xml"); print $ dom-> savexml ();?>
3. Traverse Elements
<? PHP // getnode. PHP // parse a file step // 1 create an object that represents the document $ dom = new domdocument ("1.0", "UTF-8"); // 2 formulated to load that XML, parse the file $ dom-> load ("xml_test.xml"); // 3 get your new node $ stu_nodes = $ dom-> getelementsbytagname ("student "); for ($ I = 0; $ I <$ stu_nodes-> length; $ I ++) {// retrieve each student $ stu_node = $ stu_nodes-> item ($ I ); for ($ I = 0; $ I <$ stu_node-> childnodes-> length; $ I ++) {echo $ stu_node-> childnodes-> item ($ I) -> nodevalue; echo "<br/>" ;}}?>
4. Delete Elements
<? PHP // parse a file step // 1 create an object that represents the document $ dom = new domdocument ("1.0", "UTF-8"); // 2 formulated to load that XML, parse the file $ dom-> load ("xml_test.xml"); // 3 get your new node $ stu_nodes = $ dom-> getelementsbytagname ("student "); $ stu_node = $ stu_nodes-> item ($ stu_nodes-> length-1); $ stu_node-> parentnode-> removechild ($ stu_node ); $ dom-> Save ("xml_test.xml");?>

5. Modify element attributes

<? PHP // 1 create an object that represents the document $ dom = new domdocument ("1.0", "UTF-8"); // 2 formulated to load that XML, parse the file $ dom-> load ("xml_test.xml"); // find the student $ stus = $ dom-> getelementsbytagname ("Age")-> item (0 ); $ stus-> nodevalue = 100; $ dom-> Save ("xml_test.xml");?>

The above introduces the basic Dom operation, add, delete, modify, query, the next section will have a specific instance to operate reference: http://www.php.net/manual/en/class.domdocument.php

Contact Us

The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion; products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the content of the page makes you feel confusing, please write us an email, we will handle the problem within 5 days after receiving your email.

If you find any instances of plagiarism from the community, please send an email to: info-contact@alibabacloud.com and provide relevant evidence. A staff member will contact you within 5 working days.

A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

  • Sales Support

    1 on 1 presale consultation

  • After-Sales Support

    24/7 Technical Support 6 Free Tickets per Quarter Faster Response

  • Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.