排序多維數組的數組子鍵值

Question

也有類似的問題，並張貼此答案，但他們沒有相當符合我陣列的結構，所以道歉，如果我錯過了什麼。這是由WordPress wpdb類生成的數組：

Array ( 
[0] => Array ([meta_id] => 37850 [post_id] => 5548 [meta_key] => Item # [meta_value] => 66002) 
[1] => Array ([meta_id] => 37851 [post_id] => 5548 [meta_key] => Hex Size [meta_value] => .051") 
[2] => Array ([meta_id] => 37852 [post_id] => 5548 [meta_key] => Across Flats [meta_value] => 0.051) 
[3] => Array ([meta_id] => 37853 [post_id] => 5548 [meta_key] => Type [meta_value] => Hexagonal) 
[4] => Array ([meta_id] => 37854 [post_id] => 5548 [meta_key] => Shank [meta_value] => .315")) 

Array ( 
[0] => Array ([meta_id] => 37910 [post_id] => 5553 [meta_key] => Item # [meta_value] => 66008) 
[1] => Array ([meta_id] => 37911 [post_id] => 5553 [meta_key] => Hex Size [meta_value] => 1/8") 
[2] => Array ([meta_id] => 37912 [post_id] => 5553 [meta_key] => Across Flats [meta_value] => 0.127) 
[3] => Array ([meta_id] => 37913 [post_id] => 5553 [meta_key] => Type [meta_value] => Hexagonal) 
[4] => Array ([meta_id] => 37914 [post_id] => 5553 [meta_key] => Shank [meta_value] => .315")) 

Array ( 
[0] => Array ([meta_id] => 37862 [post_id] => 5549 [meta_key] => Item # [meta_value] => 66004) 
[1] => Array ([meta_id] => 37863 [post_id] => 5549 [meta_key] => Hex Size [meta_value] => 1/16") 
[2] => Array ([meta_id] => 37864 [post_id] => 5549 [meta_key] => Across Flats [meta_value] => 0.063) 
[3] => Array ([meta_id] => 37865 [post_id] => 5549 [meta_key] => Type [meta_value] => Hexagonal) 
[4] => Array ([meta_id] => 37866 [post_id] => 5549 [meta_key] => Shank [meta_value] => .315")) 

Array ( 
[0] => Array ([meta_id] => 37886 [post_id] => 5551 [meta_key] => Item # [meta_value] => 66006) 
[1] => Array ([meta_id] => 37887 [post_id] => 5551 [meta_key] => Hex Size [meta_value] => 3/32") 
[2] => Array ([meta_id] => 37888 [post_id] => 5551 [meta_key] => Across Flats [meta_value] => 0.095) 
[3] => Array ([meta_id] => 37889 [post_id] => 5551 [meta_key] => Type [meta_value] => Hexagonal) 
[4] => Array ([meta_id] => 37890 [post_id] => 5551 [meta_key] => Shank [meta_value] => .315")) 

我需要按照Array [meta_value]的順序列出它們。然後我使用該數組按照該順序生成產品表。我一直在與下面的功能，但它產生的結果是沒有任何意義：

function subval_sort($a,$subkey) { 
    foreach($a as $k=>$v) { 
     $b[$k] = strtolower($v[$subkey]); 
    } 
    asort($b); 
    foreach($b as $key=>$val) { 
     $c[] = $a[$key]; 
    } 
    return $c; 
} 

Answer 1

使用usort()，例如：

$items = [ 
    ['id' => 3, 'item' => 'pc'], 
    ['id' => 1, 'item' => 'mouse'], 
    ['id' => 2, 'item' => 'kb'], 
]; 

function compare_id($a, $b) { 
    if ($a['id'] == $b['id']) return 0; 
    return ($a['id'] < $b['id']) ? -1 : 1; 
} 

usort($items, 'compare_id'); 

var_dump($items);  

或使用匿名函數

usort($items, function ($a, $b) { 
    if ($a['id'] == $b['id']) return 0; 
    return ($a['id'] < $b['id']) ? -1 : 1; 
});