为什么php迭代引用返回重复的最后一条记录？ [英] Why php iteration by reference returns a duplicate last record?

问题描述

我只花了2个小时来寻找一个显然来自foreach迭代的错误并带有& value。我有一个multidimentional数组，当运行时：

I just spent 2 hours hunting a bug which apparently comes from a foreach iteration with &value. I have a multidimentional array and when a ran this:

   foreach($arrayOfJsonMods as &$item){
        //TODO memcached votes
   }

并且PHP返回一个具有相同元素数的数组，但是有一个DUPLICATE最后记录。有什么我不明白这个结构吗？

and PHP returned an array with the same element count, BUT with a DUPLICATE last record. Is there something i don't understand about this structure?

我在另一台机器上运行代码，结果是一样的。

I ran the code on a different machine, and the result was the same.

推荐答案

我猜你是重用 & $ item 这里和你绊倒了一个被报告为bug一千次但是引用的正确行为的行为，这就是手册建议：

I'll guess that you're reusing &$item here and that you're stumbling across a behavior which has been reported as bug a thousand times but is the correct behavior of references, which is why the manual advises:

参考$即使在foreach循环之后，值和最后一个数组元素仍然存在。建议通过unset（）销毁它。

Reference of a $value and the last array element remain even after the foreach loop. It is recommended to destroy it by unset().

foreach($arrayOfJsonMods as &$item)
{
   //TODO memcached votes
}
unset($item);

参见 https://bugs.php.net/bug.php?id=29992

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