按子陣列數排序多維數組

Question

我對排序數組有問題。

我有這樣我的類別數組：

Array 
(
    [0] => Array 
     (
      [title] => category 
      [url] => http//mycategoryurl 
      [subcategory] => Array 
       (
        [0] => Array 
         (
          [title] => category - first 
          [url] => http//mycategoryurl 
         ) 
        [1] => Array 
         (
          [title] => category - first 
          [url] => http//mycategoryurl 
         ) 
        [2] => Array 
         (
          [title] => category - first 
          [url] => http//mycategoryurl 
         ) 
       ) 
     ) 
    [1] => Array 
     (
      [title] => category 
      [url] => http//mycategoryurl 
      [subcategory] => Array 
       (
        [0] => Array 
         (
          [title] => category - first 
          [url] => http//mycategoryurl 
         ) 
        [1] => Array 
         (
          [title] => category - first 
          [url] => http//mycategoryurl 
         ) 
        [2] => Array 
         (
          [title] => category - first 
          [url] => http//mycategoryurl 
         ) 
        [3] => Array 
         (
          [title] => category - first 
          [url] => http//mycategoryurl 
         ) 
       ) 
     ) 
    [2] => Array 
     (
      [title] => category 
      [url] => http//mycategoryurl 
      [subcategory] => Array 
       (
        [0] => Array 
         (
          [title] => category - first 
          [url] => http//mycategoryurl 
         ) 
        [1] => Array 
         (
          [title] => category - first 
          [url] => http//mycategoryurl 
         ) 
       ) 
     ) 
) 

我想排序這個數組由count(subcategory)像這樣的：

Array 
(
    [0] => Array 
     (
      [title] => category 
      [url] => http//mycategoryurl 
      [subcategory] => Array 
       (
        [0] => Array 
         (
          [title] => category - first 
          [url] => http//mycategoryurl 
         ) 
        [1] => Array 
         (
          [title] => category - first 
          [url] => http//mycategoryurl 
         ) 
        [2] => Array 
         (
          [title] => category - first 
          [url] => http//mycategoryurl 
         ) 
        [3] => Array 
         (
          [title] => category - first 
          [url] => http//mycategoryurl 
         ) 
       ) 
     ) 
    [1] => Array 
     (
      [title] => category 
      [url] => http//mycategoryurl 
      [subcategory] => Array 
       (
        [0] => Array 
         (
          [title] => category - first 
          [url] => http//mycategoryurl 
         ) 
        [1] => Array 
         (
          [title] => category - first 
          [url] => http//mycategoryurl 
         ) 
        [2] => Array 
         (
          [title] => category - first 
          [url] => http//mycategoryurl 
         ) 
       ) 
     ) 
    [2] => Array 
     (
      [title] => category 
      [url] => http//mycategoryurl 
      [subcategory] => Array 
       (
        [0] => Array 
         (
          [title] => category - first 
          [url] => http//mycategoryurl 
         ) 
        [1] => Array 
         (
          [title] => category - first 
          [url] => http//mycategoryurl 
         ) 
       ) 
     ) 
) 

請幫我在我的例子排序這個數組等。

Answer 1

使用usort函數回調：

$arr = array(); // your array 
usort($arr, function($a, $b) { return count($a['subcategory']) < $count($b['subcategory'])? -1 : 1; }); 
print_r($arr); 

Answer 2

你想使用的功能usort像這樣：

usort($arrayToSort, function($a, $b){ 
    $aCount = count($a['subcategory']); 
    $bCount = count($b['subcategory']); 
    if ($aCount == $bCount) { 
     return 0; 
    } 

    //flip the '>' to '<' for ascending sort. It is set to do descending 
    return ($aCount > $bCount) ? -1 : 1; 

});