使用PHP创建JSON对象

Question

如何使用PHP实现或创建此类型的JSON对象？

{ 
    "label": "Devices per year",
    "data": [
        [1999, 3.0], [2000, 3.9], [2001, 2.0], [2002, 1.2], [2003, 1.3], [2004, 2.5], [2005, 2.0], [2006, 3.1], [2007, 2.9], [2008, 0.9]
    ]
}

---

几次尝试后,我没有找到解决方案.例如我试过这个:

$arrayDateAndMachine = array(
    "1999"=>3.0, 
    "2000"=>3.9
);   

$arr = array(
    "label" => "Devices per year", 
    "data" => $arrayDateAndMachine
);

var_dump(json_encode($arr));

Answer 1

$obj = new stdClass();
$obj->label="Devices per year";
$obj->data = array(
    array('1999','3.0'),
    array('2000','3.9'),
    //and so on...
);

echo json_encode($obj);

Answer 2

试试这个

$arrayDateAndMachine = array(   array("1999","3.0"), 
                                array("2000","3.9")
                                );