How to add xml document content through php, add xml document with php_PHP tutorial

//1. Create a DOMDocument object. This object represents the xml file
$xmldoc = new DOMDocument();
//2. Load the xml file (specify which xml file to parse, then the dom tree node will be loaded into the memory)
$xmldoc->load("class.xml");
//3. Add a student information
//(1) Take out the desired node
$root = $xmldoc->getElementsByTagName("class")->item(0);//Return DOMElement object type
var_dump($root);
//(2)Create student node student
$stu_node = $xmldoc->createElement("student");//Return DOMElement object type
$stu_node->setAttribute("id","Big Beauty");//Add attributes to the created node, if necessary
//(3) Create name, gender, age and other nodes name, sex and age
$stu_node_name = $xmldoc->createElement("name");
$stu_node_name->nodeValue = "Da Qiao";
$stu_node_sex = $xmldoc->createElement("sex");
$stu_node_sex->nodeValue = "Female";
$stu_node_age = $xmldoc->createElement("age");
$stu_node_age->nodeValue = "25";
//(4) Mount the three nodes such as name, sex, and age to the student node
$stu_node->appendchild($stu_node_name);
$stu_node->appendchild($stu_node_sex);
$stu_node->appendchild($stu_node_age);
//(5)Mount the student node to the root node
$root->appendchild($stu_node);
//4. Save to xml document
//$xmldoc->save("class.xml");//Save it to the original xml document, which is equivalent to adding it later; if it is an xml document that does not exist, a new xml document will be created with the content of the original xml content + newly added content.
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