PHP 在保留键的同时遍历多维数组 [英] PHP Walk through multidimensional array while preserving keys

问题描述

我有一个不知道深度的多维数组.例如，该数组可能如下所示:

I've got a multidimensional array of which I can't know the depth. The array could for example look like this:

$array = array(
    1 => array(
        5 => array(
            3 => 'testvalue1'
        )
    ),
    2 => array(
        6 => 'testvalue2'
    ),
    3 => 'testvalue3',
    4 => 'testvalue4',
);

我想用这个数组创建一个目录.这意味着需要保留密钥，因为我将它们用作章节编号".例如，testvalue1"在第 1.5.3 章中.
现在我想遍历数组，同时保留所有键 - 不使用 array_walk_recursive 因为包含另一个数组的键被删除(正确?)，并且考虑到速度最好不使用嵌套的 foreach 循环.
任何建议我应该如何做到这一点?提前致谢.

PS:对于我的脚本，键是字符串(1"而不是 1)还是整数并不重要，如果将字符串作为键将使 array_walk_recursive 保留它们.

With this array I want to create a table of contents. That means the keys need to be preserved as I'm using them as "chapter numbers". For example, "testvalue1" is in chapter 1.5.3.
Now I want to walk through the array while preserving all keys - not using array_walk_recursive as the keys containing another array are dropped (correct?) and preferably not using nested foreach loops considering the speed.
Any suggestions how I should do this? Thanks in advance.

PS: For my script it doesn't matter if the keys are strings ("1" instead of 1) or integers, if having strings as key will make array_walk_recursive preserve them.

推荐答案

您可以在堆栈的帮助下迭代您的数组以构建您的目录.

You can iterate over your array with a help of a stack to build your toc.

$stack = &$array;
$separator = '.';
$toc = array();

while ($stack) {
    list($key, $value) = each($stack);
    unset($stack[$key]);
    if (is_array($value)) {
        $build = array($key => ''); # numbering without a title.
        foreach ($value as $subKey => $node)
            $build[$key . $separator . $subKey] = $node;
        $stack = $build + $stack;
        continue;
    }
    $toc[$key] = $key. ' ' . $value;
}

print_r($toc);

输出:

Array
(
    [1] => 1
    [1.5] => 1.5
    [1.5.3] => 1.5.3 testvalue1
    [2] => 2
    [2.6] => 2.6 testvalue2
    [3] => 3 testvalue3
    [4] => 4 testvalue4
)

如果需要，您也可以另外处理该级别，但这从您的问题中不清楚.

You can additionally handle the level as well if you need to, but that was not clear from your question.

array_walk_recursive 不起作用，因为它不会给你父元素的键.也请参阅此相关问题:透明地展平数组，它有一个很好的答案并且对于更通用的情况也有帮助.

array_walk_recursive does not work, because it won't give you the keys of the parent element(s). See this related question as well: Transparently flatten an array, it has a good answer and is helpful for more generic cases as well.

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