usort并不像预期的那样

Question

我有一个简单的二维数组：

$users = array(
    array('user' => 'John', 'points' => '0'), 
    array('user' => 'Paul', 'points' => '0'), 
    array('user' => 'George', 'points' => '0'), 
    array('user' => 'Ringo', 'points' => '0') 
); 

我需要points (DESC)通过name (ASC)对它们进行排序，然后。 这将是我的代码：

function sortByOrder($a, $b) { 
    if($b['points'] == $a['points']) 
     return $a['user'] - $b['user']; 
    else 
     return $b['points'] - $a['points']; 
} 

usort($users, 'sortByOrder'); 

我得到的原始顺序而非字母顺序（因为它们都具有0点目前）。为什么？

Answer 1

您需要使用array_multisort：

DEMO

$users = array(
    array('user' => 'John', 'points' => '0'), 
    array('user' => 'Paul', 'points' => '0'), 
    array('user' => 'George', 'points' => '0'), 
    array('user' => 'Ringo', 'points' => '0') 
); 

$sort = array(); 
foreach($users as $k=>$v) { 
    $sort['points'][$k] = $v['points']; 
    $sort['user'][$k] = $v['user']; 
} 

array_multisort($sort['points'], SORT_DESC, $sort['user'], SORT_ASC,$users); 

print_r($users); 

结果：

Array 
(
    [0] => Array 
     (
      [user] => George 
      [points] => 0 
     ) 

    [1] => Array 
     (
      [user] => John 
      [points] => 0 
     ) 

    [2] => Array 
     (
      [user] => Paul 
      [points] => 0 
     ) 

    [3] => Array 
     (
      [user] => Ringo 
      [points] => 0 
     ) 

) 

这DEMO不同点

Answer 2

您需要使用strcmp，所以你的函数的n应像这里这样

function sortByOrder($a, $b) { 
    if($b['points'] == $a['points']) 
    { 
     return strcmp($a['user'], $b['user']); 
    } 
    else{ 
     return $b['points'] - $a['points']; 
    } 
} 

检查：https://eval.in/585383