Question

$instance = new className();
$instance['name']

How to make it work,an example?

Answer 1

If your class implements PHP’s SPL ArrayAccess, then you will be able to reference class attributes in the manner you describe.

Taken from the tutorial I linked:

class book implements ArrayAccess {

    public $title;
    public $author;
    public $isbn;

    public function offsetExists($offset) {
        return isset($this->$offset);
    }

    public function offsetSet($offset, $value) {
        $this->$offset = $value;
    }

    public function offsetGet($offset) {
        return $this->$offset;
    }

    public function offsetUnset($offset) {
        unset($this->$offset);
    }
}

/*** a new class instance ***/
$book = new book;

/*** set some book properties ***/
$book['title']= 'Pro PHP';
$book['author'] = 'Kevin McArthur';
$book['isbn'] = 1590598199;

print_r($book);