有类似的问题和答案发布，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。这是一个由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" ) )
我需要按数组[meta_value]的顺序列出它们。然后，我使用数组生成一个按顺序排列的乘积表。我一直在使用以下函数，但它产生的结果毫无意义：
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;
}
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($items);
或使用匿名功能
usort($items, function ($a, $b) {
if ($a['id'] == $b['id']) return 0;
return ($a['id'] < $b['id']) ? -1 : 1;
});