＆QUOT; SplFixedArray重载元素的间接修改没有影响＆QUOT; [英] "Indirect modification of overloaded element of SplFixedArray has no effect"

问题描述

为什么以下

$a = new SplFixedArray(5);
$a[0] = array(1, 2, 3);
$a[0][0] = 12345; // here
var_dump($a);

产生

Notice: Indirect modification of overloaded element of SplFixedArray has no effect in <file> on line <indicated>

它是一个错误吗？你如何处理与多维SplFixedArrays呢？任何变通办法？

Is it a bug? How do you deal with multidimensional SplFixedArrays then? Any workarounds?

推荐答案

首先，这个问题是关系到实现所有类 ArrayAccess接口这不是一个特殊的问题 SplFixedArray 仅

First, the problem is related to all classes which implement ArrayAccess it is not a special problem of SplFixedArray only.

当您使用 [] 运营商，它的行为不是完全像一个数组访问来自 SplFixedArray 元素。在内部它的 offsetGet（）方法被调用，并在您的案件阵列将返回 - 而不是引用以数组。这意味着你就 $所有修改一个[0] 会迷路，除非你将其重新保存：

When you accessing elements from SplFixedArray using the [] operator it behaves not exactly like an array. Internally it's offsetGet() method is called, and will return in your case an array - but not a reference to that array. This means all modifications you make on $a[0] will get lost unless you save it back:

解决方法：

$a = new SplFixedArray(5);
$a[0] = array(1, 2, 3); 
// get element
$element = $a[0];
// modify it
$element[0] = 12345;
// store the element again
$a[0] = $element;

var_dump($a);

下面是使用标这也失败了一个例子 - 只是为了告诉你，这是不相关的只有数组元素

Here is an example using a scalar which fails too - just to show you that it is not related to array elements only.

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