PHP如何将单数组转换为多维数组？

function convertToMultiDimensionalArray($array) {
    $result = array();
    foreach ($array as $key => $value) {
        $keys = explode('_', $key);
        $tempArray = &$result;
        foreach ($keys as $k) {
            if (!isset($tempArray[$k])) {
                $tempArray[$k] = array();
            }
            $tempArray = &$tempArray[$k];
        }
        $tempArray = $value;
    }
    return $result;
}

// 示例用法
$singleArray = array(
    'a_b_c' => 1,
    'a_b_d' => 2,
    'e_f' => 3,
    'e_g' => 4
);

$multiArray = convertToMultiDimensionalArray($singleArray);
print_r($multiArray);

Array
(
    [a] => Array
        (
            [b] => Array
                (
                    [c] => 1
                    [d] => 2
                )

        )

    [e] => Array
        (
            [f] => 3
            [g] => 4
        )

)