Multidimensional associative arrays without knowing the string keys

Question

I need to be able to take an array of unknown depth and get the keys from a specific dimension without knowing their values. For instance:

$deepArray = array(
    "fooArray1_1" => array(
        "fooArray2_1" => array(
           "fooA" => "3",
           "fooB" => "foo string example 1",
            ),
        "fooArray2_2" => array(
           "fooA" => "foo number 10",
           "fooB" => "foo string example",
            ),
    ),
    "fooArray1_2" => array(
        "fooA" => "foo number 102",
        "fooB" => "foo string example 3",
    ),
);

I would like to be able to get the key from $deepArray[0][1] where in this instance should be fooArray2_2.

[array_keys()](http://php.net/manual/en/function.array-keys.php) should be helpful for you to work this out — Mark Baker, Feb 16 '18 at 18:50
For traversing a structure of unknown depth you should use a recursive function. — Sammitch, Feb 16 '18 at 18:58
So just the key `"fooArray2_2"` or you want the data under that key? — AbraCadaver, Feb 16 '18 at 19:34
@AbraCadaver and splash58. Thank you for helping. You have solved my issue. I tried to upvote both of you, but I don't have permission. — kglearning, Feb 18 '18 at 20:52
If you wanted the key then please accept @splash58's answer, if you wanted the data under that key then please accept my answer. — AbraCadaver, Feb 19 '18 at 16:35

score 0 · Answer 1 · answered Feb 16 '18 at 18:57

function getKey($arr, $path) {
    // save last step
    $s = array_pop($path);
    // go through the array to the desired point 
    foreach($path as $x) {
        $arr = $arr[array_keys($arr)[$x]];
    }
    // get target key  
    return array_keys($arr)[$s]; 
}

echo getKey($deepArray, [0,1]); // fooArray2_2

demo

AbraCadaver · Answer 2 · 2018-02-16T19:44:02.157

You say you want the key, but if you really want the data under that key; here's an example from my answer How to write getter/setter to access multi-level array by key names?, modified to use array_values to index numerically:

function get_by_offsets($path, $array) {
    $temp = &$array;

    foreach($path as $key) {
        $temp = array_values($temp);
        $temp =& $temp[$key];
    }
    return $temp;
}

$result = get_by_offsets([0, 1], $deepArray); //returns NULL if the path doesn't exist

Yields the data under $deepArray['fooArray1_1']['fooArray2_2']:

Array
(
    [fooA] => foo number 10
    [fooB] => foo string example
)

Multidimensional associative arrays without knowing the string keys

2 Answers2