Symfony\Component\Form\FieldGroup::offsetExists PHP Метод

Returns true if the bound field exists (implements the \ArrayAccess interface).

public offsetExists ( string $key ) : boolean
$key	string	The key of the bound field
Результат	boolean	true if the widget exists, false otherwise

    public function offsetExists($key)
    {
        return $this->has($key);
    }

FieldGroup