PHP多维数组搜索键

在PHP中搜索多维数组的键有多种方法，下面是一些示例代码：

1. 使用递归函数搜索多维数组的键：

function searchKey($needle, $haystack) {
    foreach($haystack as $key => $value) {
        if ($key === $needle) {
            return $value;
        }
        if (is_array($value)) {
            $result = searchKey($needle, $value);
            if ($result !== false) {
                return $result;
            }
        }
    }
    return false;
}

$array = array(
    "key1" => "value1",
    "key2" => array(
        "key3" => "value3",
        "key4" => "value4"
    )
);

$result = searchKey("key3", $array);
echo $result; // 输出：value3

2. 使用array_walk_recursive函数搜索多维数组的键：

function searchKey($needle, $haystack) {
    $result = false;
    array_walk_recursive($haystack, function($value, $key) use ($needle, &$result) {
        if ($key === $needle) {
            $result = $value;
        }
    });
    return $result;
}

$array = array(
    "key1" => "value1",
    "key2" => array(
        "key3" => "value3",
        "key4" => "value4"
    )
);

$result = searchKey("key3", $array);
echo $result; // 输出：value3

3. 使用RecursiveIteratorIterator类搜索多维数组的键：

function searchKey($needle, $haystack) {
    $iterator = new RecursiveIteratorIterator(new RecursiveArrayIterator($haystack));
    foreach($iterator as $key => $value) {
        if ($key === $needle) {
            return $value;
        }
    }
    return false;
}

$array = array(
    "key1" => "value1",
    "key2" => array(
        "key3" => "value3",
        "key4" => "value4"
    )
);

$result = searchKey("key3", $array);
echo $result; // 输出：value3

以上是几种常用的方法来搜索多维数组的键，根据实际需求选择适合的方法即可。