我正在编写一个函数来将给定 xml 文件的所有属性值重置为空字符串。有人可以帮我修复此功能以执行请求的任务吗？谢谢!

// reset all attribute values to NULL or ""
function resetAttributes($xml) {
    foreach($xml->children() as $child) {
        foreach($child->attributes() as $attr) {
            $attr = "";
        }
        resetAttributes($child);

    }
    return $xml;
}

$xml = simplexml_load_file($xmlFile);
resetAttributes($xml);
$xml->asXML($xmlFile);

//使用 Michael Berkowski 的解决方案进行修订!!内在 child 的属性保持不变。也许这是因为我的 PHP 版本？有关详细信息，请参阅底部的屏幕截图。

<?php
header('Content-type: text/plain');
$xmlString = <<<XMLSTR
<?xml version="1.0"?>
<catalog>
   <book id="bk101">
      <author>Gambardella, Matthew</author>
      <title>XML Developer's Guide</title>
      <genre>Computer</genre>
      <price>44.95</price>
      <publish_date>2000-10-01</publish_date>
      <description attr='12345'>An in-depth look at creating applications 
      with XML.</description>
      <sub attr='99'>
        <subsub attr1='asdb'/>
        <subsub attr1='asdb' attr2='xss'/>
      </sub>
   </book>
   <book id="bk102">
      <author  attr='54321' attr2='99999'>Ralls, Kim</author>
      <title>Midnight Rain</title>
      <genre>Fantasy</genre>
      <price price='88888'>5.95</price>
      <publish_date>2000-12-16</publish_date>
      <description>A former architect battles corporate zombies, 
      an evil sorceress, and her own childhood to become queen 
      of the world.</description>
   </book>
</catalog>
XMLSTR;

$xml = new RecursiveIteratorIterator(new SimpleXMLIterator($xmlString), RecursiveIteratorIterator::SELF_FIRST);
// Then just loop over it. The recursion will be automatic
foreach ($xml as $node) {
  foreach ($node->attributes() as $attr => $value) {
    // Set the attribute to an empty string the same way as in 
    // your recursive function...
    echo (string)$attr;
    $node->attributes()->$attr = '';
  }
}
// That's all, write out the XML.
echo '<pre>' . $xml->asXML() . '</pre>';

1. http://img42.com/l9tSg
2. http://img42.com/9b18L

最佳答案

你肯定在正确的轨道上，你的递归将正常工作，但在迭代属性时你应该使用 $attr => $value在foreach()并使用动态属性名称 $child->attributes()->$attr 按名称专门设置属性.这可能不是使用 SimpleXMLElement 执行此操作的唯一方法，但它很简单并且有效。

function resetAttributes($xml) {
    foreach($xml->children() as $child) {
        foreach($child->attributes() as $attr => $value) {
            // Call attributes() and identify the attribute by name
            // which you get from $attr in the iteration
            $child->attributes()->$attr = "";
        }
        // Recurse as you are doing...
        resetAttributes($child);
    }
    return $xml;
}

$xml = simplexml_load_file($xmlFile);
resetAttributes($xml);
$xml->asXML($xmlFile);

但是我们可以使用 PHP 的 SPL 迭代器做得更好...

理想情况下，您可以这样做 using a RecursiveIteratorIterator , 因为 SimpleXMLIterator 实现 RecursiveIterator界面。

// The SimpleXMLIterator constructor wants a string...
$xmlString = file_get_contents($xmlFile);
// Instantiate a new RecursiveIteratorIterator for SimpleXML
$xml = new RecursiveIteratorIterator(new SimpleXMLIterator($xmlString), RecursiveIteratorIterator::SELF_FIRST);
// Then just loop over it. The recursion will be automatic
foreach ($xml as $node) {
  foreach ($node->attributes() as $attr => $value) {
    // Set the attribute to an empty string the same way as in 
    // your recursive function...
    $node->attributes()->$attr = '';
  }
}
// That's all, write out the XML.
$xml->asXML($xmlFile);

关于php - 如何用php递归更新xml属性值？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/21869661/