如何创建一个递归函数来取消PHP中的多维数组？

Question

Below is my target array which I would like to unset its elements by key based on the candidate array element.

$target = [
    60 => "Home"
    "Villa" => [
        "30" => "Vi",
    ],
    70 => "A",
    40 => "B",
    50 => "C",
    "Land" => [
        1 => "La",
        35 => "Lb",
        37 => "Lc",
        39 => "Ld",
    ],
];

$candidate = [30, 50, 35, 37];

Below is the result that I want after unsetting.

$target = [
    60 => "Home"
    70 => "A",
    40 => "B",
    "Land" => [
        1 => "La",
        39 => "Ld",
    ],
];

'Villa' must also be gone because it's empty after it's element "30" => "Vi" has been unset.

Below my solution in for-loop.

foreach ($target as $id => $option) {
    if (isset($candidate[$id])) {
      unset($target[$id]);
    }
    elseif (is_array($option)) {
      foreach ($option as $sub_id => $opt) {
        if (isset($candidate[$sub_id])) {
          unset($target[$id][$sub_id]);
        }
      }
    }

    if (!count($target[$id])) {
      unset($target[$id]);
    }
}

How can I replace this for-loop in a recursive solution?

Answer 1

function del($target, $candidate) {
    foreach ($target as $key => $value) {
        if (in_array($key, $candidate)) {
            unset($target[$key]);
        } elseif (is_array($value)) {
            $target[$key] = del($value, $candidate);
            if (!count($target[$key])) {
                unset($target[$key]);
            }
        }
    }
    return $target;
}

$new = del($target, $candidate);
var_dump($new);