[英]How to dynamically access values in a variably multidimensional array
$first = array("a", "b" => array("c", "d" => array("e", "f")), "g", "h" => array("f"));
$second = array("b", "d", "f");
$string = "foobar";
Given the above code, how can I set a value in $first
at the indexes defined in $second
to the contents of $string
? 鉴于上面的代码,我怎样才能在$second
定义的$first
中设置一个值$string
的内容? Meaning, for this example, it should be $first["b"]["d"]["f"] = $string;
意思是,对于这个例子,它应该是$first["b"]["d"]["f"] = $string;
, but the contents of $second
and $first
can be of any length. ,但$second
和$first
的内容可以是任意长度。 $second
will always be one dimensional however. 然而, $second
总是一维的。 Here's what I had tried, which didn't seem to work as planned: 这是我尝试过的,似乎没有按计划运行:
$key = "";
$ptr = $first;
for($i = 0; $i < count($second); $i++)
{
$ptr &= $ptr[$second[$i]];
$key = key($ptr);
}
$first[$key] = $string;
This will do $first["f"] = $string;
这将是$first["f"] = $string;
instead of the proper multidimensional indexes. 而不是适当的多维索引。 I had thought that using key
would find the location within the array including the levels it had already moved down. 我原以为使用key
会找到数组中的位置,包括它已经向下移动的级别。
How can I access the proper keys dynamically? 如何动态访问正确的密钥? I could manage this if the number of dimensions were static. 如果尺寸的数量是静态的,我可以管理这个。
EDIT: Also, I'd like a way to do this which does not use eval
. 编辑:另外,我想要一种不使用eval
。
It's a bit more complicated than that. 这比那复杂一点。 You have to initialize every level if it does not exist yet. 如果尚未存在,则必须初始化每个级别。 But your actual problems are: 但你的实际问题是:
$ptr
, not in $first
. 要添加值的数组是$ptr
,而不是$first
。 $x &= $y
is shorthand for $x = $x & $y
(bitwise AND). $x &= $y
是$x = $x & $y
(按位AND)的简写。 What you want is x = &$y
(assign by reference). 你想要的是x = &$y
(通过引用分配)。 This should do it: 这应该这样做:
function assign(&$array, $keys, $value) {
$last_key = array_pop($keys);
$tmp = &$array;
foreach($keys as $key) {
if(!isset($tmp[$key]) || !is_array($tmp[$key])) {
$tmp[$key] = array();
}
$tmp = &$tmp[$key];
}
$tmp[$last_key] = $value;
unset($tmp);
}
Usage: 用法:
assign($first, $second, $string);
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