PHP从对象中的数组中获取键

Question

I've got object and I need list of it's keys.

for now I doing that in foreach

foreach($obj as $key => $attribute){
  var_dump($key);
}

Is there some PHP built in function for getting object keys like array_keys for arrays?

trace

object(Solarium\QueryType\Select\Result\Document)#1383 (1) { ["fields":protected]=> array(31) { ["pdf_url"]=> string(51) "xxxxxxxxxxxx" ["title"]=> string(150) ......

Answer 1

class A 
{
    private $a = 1;
    protected $b = 2;
    public $c = 3;
}

$object = new A();
$fields = get_object_vars($object);

But by this method, you can only get public fields from your object, i.e

print_r($fields);

Will output

Array ( [c] => 3 )