如何在PHP中将单个数组转换为多维数组？

我有一个数组，看起来像这样：

[98] => Array
(
    [City] => Caracas
    [Country] => Venezuela
    [Continent] => Latin America
)

[99] => Array
(
    [City] => Cairo
    [Country] => Egypt
    [Continent] => Middle East
)

[105] => Array
(
    [City] => Abu Dhabi
    [Country] => United Arab Emirates
    [Continent] => Middle East
)

[106] => Array
(
    [City] => Dubai
    [Country] => United Arab Emirates
    [Continent] => Middle East
)

[107] => Array
(
    [City] => Montreal
    [Country] => Canada
    [Continent] => North America
)

我尝试将此数组排序为多维数组，以便它输出如下内容：

Continent
    - Country Name    
      -- Cities under Every Country

---

我正在使用PHP。有谁能给我指出一个好的起点，告诉我应该如何做呢？

我想你只需要在数组中循环，然后创建一个新的数组，例如，使用一些值作为键，另一些值作为值

$array = array(
    98 => array(
        'City' => 'Caracas',
        'Country' => 'Venezuela',
        'Continent' => 'Latin America',
    ),
    99 => array(
        'City' => 'Cairo',
        'Country' => 'Egypt',
        'Continent' => 'Middle East',
    ),
    105 => array(
        'City' => 'Abu Dhabi',
        'Country' => 'United Arab Emirates',
        'Continent' => 'Middle East',
    ),
    106 => array(
        'City' => 'Dubai',
        'Country' => 'United Arab Emirates',
        'Continent' => 'Middle East',
    ),
    107 => array(
        'City' => 'Montreal',
        'Country' => 'Canada',
        'Continent' => 'North America',
    )
);

$newArray = array();
foreach ($array as $row)
{
   $newArray[$row['Continent']][$row['Country']][] = $row['City'];
}

print_r($newArray);

$new_array = array();
foreach($array as $val)
{ 
     $new_array[$val['Continent']][$val['Country']] = array('City' => $val['City']);
}  

---

出于好奇，数组是如何生成的？我有一个返回数组的SQL查询。也许通过SQL分组来组织数据更容易。标题的可能重复会产生误导。问题是如何将一个多维数组转换为另一个具有不同结构的多维数组。