需要根据二维数组里面的某一个数组排序

$arr = array('0' => array(     'num1' => 3,     'num2' => 27    ),   '1' => array(       'num1' => 5,      'num2' => 50   ),  '2' => array(      'num1' => 4,       'num2' => 44   ),   '3' => array(      'num1' => 3,      'num2' => 78  )  ); foreach ( $arr as $key => $row ){     $num1[$key] = $row ['num1'];     $num2[$key] = $row ['num2']; } array_multisort($num1, SORT_ASC, $num2, SORT_DESC, $arr); print_r($arr); //result: Array(     [0]=>Array([num1]=>3 [num2]=>78)      [1]=>Array([num1]=>3 [num2]=>27)      [2]=>Array([num1]=>4 [num2]=>44) [3]=>Array([num1]=>5 [num2]=>50))