unset() 在类方法中不起作用

Question

我有一个类说，Foo，它有一个名为 bar 的 json 字符串属性：[PHP Fiddle Link]

<?php


class Foo {

    public $bar = '{"1455260079":"Tracking : #34567808765098767 USPS","1455260723":"Delivered","1455261541":"Received Back"}';

    public function getBar(){
        return (array) json_decode($this->bar);
    }

    public function remove($timestamp){

        $newBar = $this->getBar();

        print_r($newBar);

        unset($newBar[$timestamp]);

        print_r($newBar); 

        $this->bar = json_encode($newBar);

    }

}

现在，要从 bar 中删除一个元素，我正在执行以下操作，我无法弄清楚它为什么不删除：

$foo = new Foo();
$foo->remove("1455261541");
echo $foo->bar;

打印出来：

Array
(
    [1455260079] => Tracking : #34567808765098767 USPS
    [1455260723] => Delivered
    [1455261541] => Received Back
)
Array
(
    [1455260079] => Tracking : #34567808765098767 USPS
    [1455260723] => Delivered
    [1455261541] => Received Back
)
{"1455260079":"Tracking : #34567808765098767 USPS","1455260723":"Delivered","1455261541":"Received Back"}

这背后的原因是什么？有什么帮助吗？

Answer 1

尝试以下解决方案，我只是更改了getBar 函数并在json_decode 函数中添加了一个参数：

class Foo {

    public $bar = '{"1455260079":"Tracking : #34567808765098767 USPS","1455260723":"Delivered","1455261541":"Received Back"}';

    public function getBar(){
        return json_decode($this->bar, true);
    }

    public function remove($timestamp){

        $newBar = $this->getBar();

        print_r($newBar);

        unset($newBar[$timestamp]);

        print_r($newBar);

        $this->bar = json_encode($newBar);

    }

}

$foo = new Foo();
$foo->remove("1455261541");
echo $foo->bar;

输出：

Array
(
    [1455260079] => Tracking : #34567808765098767 USPS
    [1455260723] => Delivered
    [1455261541] => Received Back
)
Array
(
    [1455260079] => Tracking : #34567808765098767 USPS
    [1455260723] => Delivered
)
{"1455260079":"Tracking : #34567808765098767 USPS","1455260723":"Delivered"}