PHP删除重复的键并将值组合到多维数组中

function combineValues($array) {
    $result = array();

    foreach ($array as $key => $value) {
        if (!array_key_exists($key, $result)) {
            $result[$key] = $value;
        } else {
            if (is_array($result[$key])) {
                $result[$key][] = $value;
            } else {
                $result[$key] = array($result[$key], $value);
            }
        }
    }

    return $result;
}

// 示例用法
$input = array(
    'a' => 'value 1',
    'b' => 'value 2',
    'c' => 'value 3',
    'a' => 'value 4',
    'd' => 'value 5',
    'b' => 'value 6'
);

$result = combineValues($input);
print_r($result);

Array
(
    [a] => Array
        (
            [0] => value 1
            [1] => value 4
        )
    [b] => Array
        (
            [0] => value 2
            [1] => value 6
        )
    [c] => value 3
    [d] => value 5
)