PHP：documentElement-> childNodes警告 [英] PHP: documentElement->childNodes warning

问题描述

$xml = file_get_contents(example.com);

$dom = new DomDocument();
$dom->loadXML($xml);

$items = $dom->documentElement;

foreach($items->childNodes as $item) { 
 $childs = $item->childNodes;
 foreach($childs as $i) {
  echo $i->nodeValue . "<br />";
 }
}

现在我在每2nd foreach中都会收到此警告：

Now I get this warning in every 2nd foreach:

Warning: Invalid argument supplied for foreach() in file_example.php  on line 14

请帮助大家。谢谢！

推荐答案

某些节点没有子节点，因此您将一个null（无效）参数传递给foreach（就像警告说的那样。）

Some nodes don't have children, so you're passing a null (invalid) argument to the foreach (just like the warning says).

要避免出现警告，您需要检查当前节点是否有任何子节点。为此，您可以使用 DOMNode :: hasChildNodes（） 方法：

To avoid the warnings you need to check if the current node has any children. For that you can use the DOMNode::hasChildNodes() method:

foreach($items->childNodes as $item) { 
    if ($item->hasChildNodes()) {
        $childs = $item->childNodes;
        foreach($childs as $i) {
            echo $i->nodeValue . "<br />";
        }
    }
}

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