Question

下面是我的目标数组，我希望根据候选数组元素按键取消其元素。

$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];

以下是取消设置后我想要的结果。

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

＆＃39;别墅＆＃39;也必须消失，因为它的元素＆＃34; 30＆＃34; =＆GT; ＆＃34;六＆＃34;一直未设置。

在我的for-loop解决方案之下。

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]);
    }
}

如何在递归解决方案中替换此for循环？

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);

Answer 2

这开头是对Mehdi回答的评论，但我的空间不足了：

虽然我认为数组是通过引用传递的，并且应该有最小的开销来分配对它来自的变量的引用，但是我明白通过引用显式传递可能更健壮和透明。

即

function clean(&$target, $candidate, $depth=0){
   if (++$depth>10) {
      // erk!
      trigger_error("Too deep!");
   }
   // Loop through candidates
   foreach($candidate as $index){
       // If the value is an array
       if(isset($target[$index]) && is_array($target[$index])){
           clean($target[$index], $candidate, $depth);
           if (!count($target[$index])) unset($target[$index]); // thanks jhilgeman
       } else {
           isset($target[$index]) && unset($target[$index]);
       }
   }
}

clean($target, $candidate);
var_dump($target);

Answer 3

修改

<?php $target = [ 60 => "Home", "Villa" => [ "30" => "Vi", ], 70 => "A", 40 => "B", 50 => "C", "Land" => [ 1 => "La", 35 => "Lb", 37 => "Lc", 39 => "Ld", ], ]; $candidate = [30, 50, 35, 37]; function clean(&$target, $candidate){ // Loop through target foreach($target as $index => $value){ // If the value is an array if(is_array($value)){ // Clean it first $result = clean($value, $candidate); $target[$index] = $result; } else { // Check if the key is in the candidate array if(in_array($index, $candidate)){ $target[$index] = NULL; } } // If the value is empty if(empty($target[$index])){ // Unset it unset($target[$index]); } } } $target = clean($target, $candidate); var_dump($target);

结果：

/var/www/test.php:47: array (size=4) 60 => string 'Home' (length=4) 70 => string 'A' (length=1) 40 => string 'B' (length=1) 'Land' => array (size=2) 1 => string 'La' (length=2) 39 => string 'Ld' (length=2)

正如 symcbean 提到的那样使用引用会更好

如何创建一个递归函数来取消PHP中的多维数组？

3 个答案: