php多维数组的指定单个字段排序

多维数组如何根据指定键值？比如现在有数组结构如下：

$data = array(
    0 => array('name' => '1班','avgScore'=>90,'subject' => 'math'),
    1 => array('name' => '2班','avgScore'=>60,'subject' => 'math'),
    2 => array('name' => '3班','avgScore'=>88,'subject' => 'math' ),
);

如何把它变成：

$data = array(
    0 => array('name' => '1班','avgScore'=>,'subject' => 'math'),
    1 => array('name' => '3班','avgScore'=>88,'subject' => 'math'),
    2 => array('name' => '2班','avgScore'=>60,'subject' => 'math'),
);

1、array_multisort()

可使用 array_multisort()函数排序，

function mySort($arr = array(),$sort_by){
    foreach($arr as $k => $v){
        $avgScore[$k] = $v[$sort_by];
    }
    array_multisort($avgScore, SORT_DESC, $arr);
    return $arr;
}

echo "<pre>";
print_r(mySort($data),'avgScore');

输出：

$data = array(
    0 => array('name' => '1班','avgScore'=>,'subject' => 'math'),
    1 => array('name' => '3班','avgScore'=>88,'subject' => 'math'),
    2 => array('name' => '2班','avgScore'=>60,'subject' => 'math'),
);