在关联数组中按值搜索并返回其键

Question

What is the easiest way to search in such an array? Eg search for 5f8ff7a0c49db9d and return 5f8ff7bee02fd05

This doesn't work:

array_search('5f8ff7a0c49db9d', array_column($arr, 1))


[0] : Array
(
    [0] => Array
        (
            [5f8ff7bedde211e] => 5f8e6a74c1d4efe
        )

    [1] => Array
        (
            [5f8ff7bee02fd05] => 5f8ff7a0c49db9d
        )

    [2] => Array
        (
            [5f8ff7bee2735ce] => 5f8ff7a0c6e8039
        )

)

Answer 1

You can reduce the whole array as following:

$keyedByValue = array_reduce($arr, static function(array $carry, array $item) {
    return array_merge($carry, array_reverse($item));
}, []);

$yourKey = $keyedByValue['5f8ff7a0c49db9d'];

Or you can even use a simple loop:

$result = null;
$search = '5f8ff7a0c49db9d';

foreach ($arr as $item) {
    $item = array_reverse($item);

    if (isset($item[$search])) {
         $result = $item[$search];
         break;
    }
}

Answer 2

array_search has this in the examples:

$foundKey = array_search($needle, array_column($array, 'key')); 

which works fine