PHP的foreach仅返回键 [英] PHP foreach that returns keys only

问题描述

理论问题，也许没有任何意义，但仍然，也许是一个聪明的回答。

Theoretical question that perhaps does not make any sense but still, maybe there is a clever answer.

我想通过数组进行迭代，并获得其钥匙和东西他们。我做什么一个简单的例子：

I want to iterate through array and get its keys and to something with them. A quick example of what I do:

foreach($array as $key => $value) {
    $other_array[$key] = 'something';
}

现在， PHP混乱探测器尖叫了 $值在此范围内使用。所以我在想，也许这是不是我的阵列访问键的最佳途径。

Now, PHP Mess Detector screams that $value is unused in this scope. Therefore I was thinking that perhaps this is not the best way to access keys of my array.

任何想法如何做到这一点，避免不必要的取出值我的阵列？是否有任何显著的性能影响......或许我只是被偏执并应随身携带，不浪费任何人的时间愚蠢的问题。）

Any idea how to do it without unnecessarily taking out values out of my array? Does it have any significant performance impact ... or perhaps I am just being paranoid and should carry on without wasting anyone's time with stupid questions :).

推荐答案

您可以做这样的事情。

foreach(array_keys($array) as $key) {
 // do your stuff
}

这将使的的foreach 的迭代由来自阵列，而不是实际的数组中的键的数组。请注意，这可能不是从性能的角度来看，虽然好

That would make the foreach iterate over an array consisting of the keys from your array instead of the actual array. Note that it's probably not better from a performance standpoint though.

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