如何使用 SimpleXML 检查元素是否存在? [英] How to check if element exists with SimpleXML?

问题描述

我有以下内容(简化的 XML):

I have the following (simplified XML):

<?xml version="1.0" encoding="UTF-8" ?>

<products>
  <product>
    <artnr>xxx1</artnr>
  </product>
</products>

以及以下(再次简化的 PHP 代码):

And the following (again simplified PHP code):

$xml= @simplexml_load_file($filename);

foreach ($xml->product as $product) {
    if (!$this->validate_xml_product($product)) {
        continue;
    }
}

function validate_xml_product($product)
{
    if (!property_exists('artnr', $product)) {
        // why does it always validate to true?
    }
}

由于某种原因，产品从未通过验证.

For some reason the product never validates.

property_exists 不是判断$product 中是否有artnr 元素的正确方法吗?

Isn't property_exists the correct way of finding out whether there is an artnr element in $product?

推荐答案

代码中参数的顺序颠倒了.正确的是首先是对象然后是属性名称:

The order of parameter in your code is reversed. Correct is first the object then the property-name:

if (!property_exists($product, 'artnr')) {

显然这仅适用于真实"属性.如果属性是使用 __get-Method 实现的，这也不起作用.

And apparently this only works for "real" properties. If the property is implemented using the __get-Method this won't work either.

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