求大神解答一个关于foreach的有关问题

    
        
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$mid=$xml2->getElementsByTagName("middle")->item(0);
foreach($mid->childNodes as $v1){
        echo $v1->tagName;
        foreach($v1->childNodes as $c2){
            echo $c2->tagName;
            echo $c2->nodeValue;
        }
    }