PHP中的数组到对象和对象到数组-有趣的行为-ArraytoObjectandObjecttoArrayinPHP-interestingbehaviour

Can you explain the next interesting behaviour?

你能解释下一个有趣的行为吗？

class test {
  //Class *test* has two properties, public and private.
  public $xpublic = 'x1';
  private $xprivate = 'x2';
}
$testObj = new test();

Let's convert $testObj to array.

让我们将$ testObj转换为数组。

settype($testObj, 'array');
var_dump($testObj);

Result:

结果：

array(2) {
  ["xpublic"]=> string(3) "x1"
  ["testxprivate"]=> string(4) "x2"
}

OK, xprivate property becomes testxprivate

好的，xprivate属性变为testxprivate

Let's convert this array to object.

让我们将这个数组转换为object。

$newObj = (object)$testObj;
var_dump($newObj);

Result:

结果：

object(stdClass)#1 (2) {
  ["xpublic"]=> string(3) "xxx"
  ["xprivate":"test":private]=> string(4) "xxx3"
}

$newObj is a stdClass object.

$ newObj是一个stdClass对象。

And the question is:

问题是：

Why does testxprivate become a private property xprivate (not testxprivate) of the new object? How does PHP know that $testObj array was an object?

为什么testxprivate成为新对象的私有属性xprivate（而不是testxprivate）？ PHP如何知道$ testObj数组是一个对象？

If I define the equal array:

如果我定义相等的数组：

$testArray = array('xpublic'=>'x1', 'testxprivate'=>'x2');

and then convert it to object:

然后将其转换为对象：

var_dump((object)$testArray);

I'll get the object with two public properties xpublic and testxprivate as expected:

我将按预期获得具有两个公共属性xpublic和testxprivate的对象：

object(stdClass)#2 (2) {
  ["xpublic"]=> string(2) "x1"
  ["testxprivate"]=> string(2) "x2"
}

2 个解决方案

$array = array(
    "xpublic" => "x1", 
    # this will become a private member:
    "\x00test\x00xprivate" => "x2",
    # this will become a protected member:
    "\x00*\x00xprotected" => "x3"
);

var_dump($array);

$obj = (object) $array;

var_dump($obj);

array(3) {
  ["xpublic"]=>
  string(2) "x1"
  ["testxprivate"]=>
  string(2) "x2"
  ["*xprotected"]=>
  string(2) "x3"
}

object(stdClass)#1 (3) {
  ["xpublic"]=>
  string(2) "x1"
  ["xprivate":"test":private]=>
  string(2) "x2"
  ["xprotected":protected]=>
  string(2) "x3"
}