PHP-自动创建多维数组 [英] PHP - Automatically creating a multi-dimensional array

问题描述

所以这是输入:

$in['a--b--c--d'] = 'value';

和所需的输出:

$out['a']['b']['c']['d'] = 'value';

有什么想法吗?我已经尝试了下面的代码，但没有任何运气...

Any ideas? I've tried the following code without any luck...

$in['a--b--c--d'] = 'value';
// $str = "a']['b']['c']['d";
$str = implode("']['", explode('--', key($in)));
${"out['$str']"} = 'value';

推荐答案

这似乎是递归的主要候选对象.

This seems like a prime candidate for recursion.

基本方法如下:

1. 创建键数组
2. 为每个键创建一个数组
3. 没有更多键时，返回值(而不是数组)

下面的递归精确地做到了这一点，在每次调用期间创建一个新数组，将列表中的第一个键指定为新值的键.在下一步中，如果还有键，则重复该过程，但是当没有键时，我们只返回该值.

The recursion below does precisely this, during each call a new array is created, the first key in the list is assigned as the key for a new value. During the next step, if there are keys left, the procedure repeats, but when no keys are left, we simply return the value.

$keys = explode('--', key($in));

function arr_to_keys($keys, $val){
    if(count($keys) == 0){
        return $val;
    }
    return array($keys[0] => arr_to_keys(array_slice($keys,1), $val));
}

$out = arr_to_keys($keys, $in[key($in)]);

对于您的示例，上面的代码将被评估为与此等效(但在任何数量的--分隔项目的一般情况下都适用):

For your example the code above would evaluate as something equivalent to this (but will work for the general case of any number of -- separated items):

$out = array($keys[0] => array($keys[1] => array($keys[2] => array($keys[3] => 'value'))));

或更确切地说，它构造以下内容:

Or in more definitive terms it constructs the following:

$out = array('a' => array('b' => array('c' => array('d' => 'value'))));

这允许您通过所需的索引访问每个子数组.

Which allows you to access each sub-array through the indexes you wanted.

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