php - 按子数组键值对多维数组进行排序

Question

为此发布了类似的问题和答案，但没有一个与我的数组结构完全匹配，所以如果我错过了什么，请道歉。这是由 WordPress wpdb 类生成的数组：

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 Array[meta_value] 的顺序列出它们。然后我使用该数组按该顺序生成产品表。我一直在使用以下函数，但它产生的结果没有任何意义：

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);    

或使用匿名函数

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