Php 数组合并并显示空数据

我有两个数组，如下所示

$array1 = array("color" => "red","size" => "32");
$array2 = array("color" => "blue","width" => "40");

我的php代码如下

    <?php
        $array1 = array("color" => "red","size" => "32");
        $array2 = array("color" => "blue","width" => "40");
        $result = array_merge_recursive($array1, $array2);
        echo json_encode($result);
?>

我想得到像这样的输出

{
color: [
"red",
"blue"
],
size: [
"32",
""
],
width: [
"",
"40"
]
}

我怎么能得到这个？请快点帮我

---

提前感谢。

使用数组\u与默认值数组合并

$array1 = array("color" => "red","size" => "32");
$array2 = array("color" => "blue","width" => "40");
$arrayInit = array("color" => "","width" => "","size"=>"");
$array1 = array_merge($arrayInit,$array1);
$array2 = array_merge($arrayInit,$array2);
$result = array_merge_recursive($array1, $array2);
echo json_encode($result);

$array1 = array("color" => "red","size" => "32");
$array2 = array("color" => "blue","width" => "40");
$arrayInit = array("color" => "","width" => "","size"=>"");
$array1 = array_merge($arrayInit,$array1);
$array2 = array_merge($arrayInit,$array2);
$result = array_merge_recursive($array1, $array2);
echo json_encode($result);

$keys = array_keys(array_merge($array1, $array2)); // get all the keys
foreach ($keys as $key) {
    // set each key in the result array to the value from the input array or a default ''
    $result[$key][] = isset($array1[$key]) ? $array1[$key] : '';
    $result[$key][] = isset($array2[$key]) ? $array2[$key] : '';
}
echo json_encode($result);