php 二维数组根据某个字段排序

function list_sort_by($list, $field, $sortby = 'desc')
{
if (is_array($list))
{
$refer = $resultSet = array();
foreach ($list as $i => $data)
{
$refer[$i] = &$data[$field];
}
switch ($sortby)
{
case 'asc': // 正向排序
asort($refer);
break;
case 'desc': // 逆向排序
arsort($refer);
break;
case 'nat': // 自然排序
natcasesort($refer);
break;
}
foreach ($refer as $key => $val)
{
$resultSet[] = &$list[$key];
}
return $resultSet;
}
return false;
}