Question

<?
stdClass Object
(
    [image_header] => Array
        (
            [0] => stdClass Object
                (
                    [img] => /headers/header.jpg
                )
        )
)
?>

Object name image_header is variable, so it can be any string. Can I access this string without knowing what it is?

@Jon his answer was satisfying for me.

For others who want to use variable objectnames this way:
To acces this object with the variablename I had to use curly brackets:

$key = key(get_object_vars($_json));
$_json->{$key}[0]->img;

Answer 1

You can do it conveniently with get_object_vars:

$propertyName = key(get_object_vars($object));