php嵌套的foreach不工作

我得到的结果是：

   //connects to mongo
   $collection  = (new MongoDB\Client)->mfrmls->properties;

   //takes array with data from array of objects            
   foreach ($obj as $k => $v){

    //prints to make sure on the right record.  this works fine
    echo "object {$v['ListingId']} \n";

    // creates a query to the mongo DB, which works fine, i have checked via var_dump
    $cursor = $collection->find(['ListingId'  => $v['ListingId']]);

    //this for each will never print anything it just seems to be skipped.
    //if i take it out of the nested foreach it works fine.
    foreach($cursor as $document) {
            echo "no no \n";
            }
    }

这显然缺少第二个for循环回波

---

仅供参考。“$cursor”只在foreach语句运行时被调用，我想这就是mongoDB-PHP的工作方式。

foreach

只在数组上迭代。

---

您可以使用

var\u dump（$cursor）检查
$cursor
的数据类型
您的代码缺少一些检查。试试这个：

object G4849756 
object A4202291 
object O5548422 
object O5548513 
object D5921405 

尝试添加一个
var\u转储（$cursor）设置后立即查找其中真正的内容。我也在想（我必须确认）在对其使用
foreach
之前，您可能需要将其从对象转换为数组。不确定。
MongoDB\Driver\Cursor对象（[database]=>mfrmls[collection]=>properties[query]=>MongoDB\Driver\query对象（[filter]=>stdClass对象（[ListingId]=>D5921405）[options]=>stdClass对象（[serverId]=>1）[readConcern]=>）
应该对这种类型的对象没有问题。在其他条件下回显某个对象并检查，它是否来自foreach？它是一个对象，MongoDB\Driver\Cursor对象（[database]=>mfrmls[collection]=>properties[query]=>MongoDB\Driver\Query对象
//connects to mongo
   $collection  = (new MongoDB\Client)->mfrmls->properties;

   //takes array with data from array of objects            
   foreach ($obj as $k => $v){

    //prints to make sure on the right record.  this works fine
    echo "object {$v['ListingId']} \n";

    // creates a query to the mongo DB, which works fine, i have checked via  
    $cursor = $collection->find(['ListingId'  => $v['ListingId']]);
print_r( $cursor);
    //this for each will never print anything it just seems to be skipped.
    //if i take it out of the nested foreach it works fine.
    if((is_array($cursor) || is_object($cursor)) && !empty( $cursor)) {
       foreach($cursor as $document) {
            echo "no no \n";
            }
     }
    }