按值排序php数组未按预期工作

Question

在数组上执行以下操作后，我得到此结果。不应该按'computer_name'排序吗？你会看到他们不是字母顺序。

usort($test, function($a, $b) { 
    return $a['computer_name'] - $b['computer_name']; 
}); 

echo "<pre>"; 
print_r($test); 
echo "</pre>"; 


Array 
(
    [0] => Array 
     (
      [computer_id] => 367 
      [account_id] => 1 
      [computer_name] => EXAMPLE_ONE 
      [last_username] => muah 
      [timestamp] => 2014-01-01 17:06:04 
     ) 

    [1] => Array 
     (
      [computer_id] => 366 
      [account_id] => 1 
      [computer_name] => TESTING 
      [last_username] => 
      [timestamp] => 2013-12-06 20:02:14 
     ) 

    [2] => Array 
     (
      [computer_id] => 365 
      [account_id] => 1 
      [computer_name] => JOE-SCHMOE 
      [last_username] => 
      [timestamp] => 2013-12-06 20:02:03 
     ) 

    [3] => Array 
     (
      [computer_id] => 18 
      [account_id] => 1 
      [computer_name] => SPORT-ONE 
      [last_username] => 
      [timestamp] => 2012-10-16 03:31:22 
     ) 

    [4] => Array 
     (
      [computer_id] => 3 
      [account_id] => 1 
      [computer_name] => SPORT-TWO 
      [last_username] => 
      [timestamp] => 2011-03-03 03:35:46 
     ) 

) 

Answer 1

我认为这个问题是EXAMPLE_ONE - TESTING，或EXAMPLE_ONE - SPORT-ONE总是等于0。

你可以尝试使用strcasecmp这里，或不区分大小写的版本strcmp

其实，在看文档对于usort，这里有一个例子。你上面的例子会像

usort($test, function($a, $b) { 
    return strcmp($a['computer_name'], $b['computer_name']); 
});