PHP 中的数组到对象和对象到数组 - 有趣的行为 [英] Array to Object and Object to Array in PHP - interesting behaviour
问题描述
你能解释下一个有趣的行为吗?
类测试{//Class *test* 有两个属性,public 和 private.公共 $xpublic = 'x1';私人 $xprivate = 'x2';}$testObj = 新测试();
让我们将 $testObj
转换为数组.
settype($testObj, 'array');var_dump($testObj);
结果:
数组(2){["xpublic"]=> 字符串(3) "x1"[testxprivate"]=> 字符串(4)x2"}
好的,xprivate
属性变成了 testxprivate
让我们将此数组转换为对象.
$newObj = (object)$testObj;var_dump($newObj);
结果:
object(stdClass)#1 (2) {["xpublic"]=> 字符串(3) "xxx"["xprivate":"test":private]=> string(4) "xxx3"}
$newObj
是一个 stdClass
对象.
问题是:
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?
如果我定义相等数组:
$testArray = array('xpublic'=>'x1', 'testxprivate'=>'x2');
然后将其转换为对象:
var_dump((object)$testArray);
我将按预期获得具有两个 public 属性 xpublic
和 testxprivate
的对象:
object(stdClass)#2 (2) {["xpublic"]=> 字符串(2) "x1"[testxprivate"]=> 字符串(2)x2"}
数组键包含一个标记,表明这应该是类测试的私有属性.
将您的脚本输出与以下内容进行比较:
$array = array(xpublic" =>"x1",# 这将成为私人成员:"\x00test\x00xprivate" =>"x2",# 这将成为受保护的成员:"\x00*\x00xprotected" =>x3");var_dump($array);$obj = (object) $array;var_dump($obj);
序列化时,相同的字符串用于描述私有成员.
输出:
<前>数组(3){["xpublic"]=>字符串(2)x1"["testxprivate"]=>字符串(2)x2"["*xprotected"]=>字符串(2)x3"}对象(标准类)#1(3){["xpublic"]=>字符串(2)x1"["xprivate":"test":private]=>字符串(2)x2"["xprotected":protected]=>字符串(2)x3"}在var_dump()
的输出中,空字节不可见.
(更新:添加了受保护的类成员)
Can you explain the next interesting behaviour?
class test {
//Class *test* has two properties, public and private.
public $xpublic = 'x1';
private $xprivate = 'x2';
}
$testObj = new test();
Let's convert $testObj
to array.
settype($testObj, 'array');
var_dump($testObj);
Result:
array(2) { ["xpublic"]=> string(3) "x1" ["testxprivate"]=> string(4) "x2" }
OK, xprivate
property becomes testxprivate
Let's convert this array to object.
$newObj = (object)$testObj;
var_dump($newObj);
Result:
object(stdClass)#1 (2) { ["xpublic"]=> string(3) "xxx" ["xprivate":"test":private]=> string(4) "xxx3" }
$newObj
is a stdClass
object.
And the question is:
Why does testxprivate
become a private property xprivate
(not testxprivate
) of the new object? How does PHP know that $testObj
array was an object?
If I define the equal array:
$testArray = array('xpublic'=>'x1', 'testxprivate'=>'x2');
and then convert it to object:
var_dump((object)$testArray);
I'll get the object with two public properties xpublic
and testxprivate
as expected:
object(stdClass)#2 (2) { ["xpublic"]=> string(2) "x1" ["testxprivate"]=> string(2) "x2" }
The array key contains a marker that this should be a private property of the class test.
Compare your scripts output with the following:
$array = array(
"xpublic" => "x1",
# this will become a private member:
"\x00test\x00xprivate" => "x2",
# this will become a protected member:
"\x00*\x00xprotected" => "x3"
);
var_dump($array);
$obj = (object) $array;
var_dump($obj);
When serialized, the same string is used to describe the private members.
Output:
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" }
In the output of var_dump()
, the null bytes are not visible.
(Update: Added protected class member)
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