php修改xml文件的方法：首先打开xml文件；然后遍历一下xml文档；接着对xml文件内容进行重新赋值；最后保存文件即可。
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php 修改和删除xml内容的原理和方法
例如：
example.xml
<?xml version="1.0" encoding="utf-8"?><root> <book id="1"> <title>title1</title> </book> <book id="2"> <title>title2</title> </book> <book id="3"> <title>title3</title> </book> <book id="4"> <title>title4</title> </book> <book id="5"> <title>title5</title> </book></root>首先遍历一下该xml文档
<?php $doc = new domdocument(); $doc->load('example.xml'); $books = $doc -> getelementsbytagname("book"); //遍历 foreach ($books as $book) { echo $book->getattribute('id')."-"; echo $book->getelementsbytagname("title")->item(0)->nodevalue; echo "<br>"; }运行结果为：
1-title1
2-title2
3-title3
4-title4
5-title5
修改：
<?php $doc = new domdocument(); $doc->load('example.xml'); $books = $doc -> getelementsbytagname("book"); //遍历 foreach ($books as $book) { //将id=3的title设置为33333 if($book->getattribute('id')==3){ echo $book->getattribute('id')."-"; echo $book->getelementsbytagname("title")->item(0)->nodevalue="33333"; echo "<br>"; } } //对文件做修改后，一定要记得重新sava一下，才能修改掉原文件 $doc -> save('example.xml');修改之后为：
<?xml version="1.0" encoding="utf-8"?><root> <book id="1"> <title>title1</title> </book> <book id="2"> <title>title2</title> </book> <book id="3"> <title>33333</title> </book> <book id="4"> <title>title4</title> </book> <book id="5"> <title>title5</title> </book></root>删除操作：
<?php $doc = new domdocument(); $doc->load('example.xml'); $root = $doc -> documentelement;//根标签 $books = $doc -> getelementsbytagname("book"); //遍历 foreach ($books as $book) { //将id=4的删除 if($book->getattribute('id')==4){ $root->removechild($book); } } //对文件做修改后，一定要记得重新sava一下，才能修改掉原文件 $doc -> save('example.xml');删除后的结果为：
<?xml version="1.0" encoding="utf-8"?><root> <book id="1"> <title>title1</title> </book> <book id="2"> <title>title2</title> </book> <book id="3"> <title>33333</title> </book> <book id="5"> <title>title5</title> </book></root>