PHP函数usort根据自定义的比较函数对二维数组进行排序

[guess_subject] => Array
	(
		[0] => Array
		(
			[subject_id] => 4587
			[game_id] => 9228
			[parent_category_id] => 78
			[subject_date_time] => 1490668200
			[status] => 2
		)
	
		[1] => Array
		(
			[subject_id] => 4588
			[game_id] => 9228
			[parent_category_id] => 78
			[subject_date_time] => 1490668200
			[status] => 2
			
	
		)
	
		[2] => Array
		(
			[subject_id] => 4584
			[game_id] => 9228
			[parent_category_id] => 78
			[subject_date_time] => 1490668200
			[status] => 1
		)
	
		[3] => Array
		(
			[subject_id] => 4585
			[game_id] => 9228
			[parent_category_id] => 78
			[subject_date_time] => 1490668200
			[status] => 2
		)
	)

foreach($data as $key => &$value) {
	// 本函数将用用户自定义的比较函数对一个数组中的值进行排序。
	// 如果要排序的数组需要用一种不寻常的标准进行排序，那么应该使用此函数。
	// 在第一个参数小于，等于或大于第二个参数时，该比较函数必须相应地返回一个小于，等于或大于 0 的整数。
	usort($value['guess_subject'], function($a, $b){
		if ($a['status'] == $b['status']) return 0;
		return ($a['status'] < $b['status']) ? -1 : 1;
	});
}
return $data;