Having hash map (get by key) like in java in PHP?

Having hash map (get by key) like in java in PHP?

Well I've thought of having ArrayList in PHP because it was extremely
useful in PHP, and saving a lot of time.
I thought it'd be cool to have in PHP, so I did make an arrayList class in
PHP:
Class ArrayList
{
public $arrayList;
function __construct()
{
$this->arrayList = array();
}
public function add($element)
{
$this->arrayList[] = $element;
}
public function remove($index)
{
if (is_numeric($index)) {
unset($this->arrayList[$index]);
}
}
public function get($index)
{
return $this->arrayList[$index];
}
}
Now, I noticed I need an list type more of a hashmap, so I can get items
by keys. Let's say I need to get mysql db name, so Ill just do
$data->hashmap->get("db_name"). This will return the database name value.
Is there a way to do this?