php - 如何重建没有重复和其他限制的数组？

Question

我有一个应用程序，允许人们提供自定义评估。我根据客户的要求建立了一种新的评分机制，允许参与者根据对他们来说更准确的方式在两个问题之间进行选择。问题是我需要随机化问题，确保同一类别中的两个问题不会一起出现，并对其进行限制，以便同一两个类别中的两个问题仅比较三次。

我尝试改编此处其他问题的代码/答案，但它们都没有直接适用，而且我很难改编最接近的代码/答案。

这是我的原始数组中的一个示例，其中包含问题(已经随机化，但没有其他标准)...

Array
(
    [0] => Array
        (
            [question_id] => 2087
            [category_id] => 287
            [question] => Question would appear here
        )

    [1] => Array
        (
            [question_id] => 2068
            [category_id] => 286
            [question] => Question would appear here
        )

    [2] => Array
        (
            [question_id] => 2067
            [category_id] => 286
            [question] => Question would appear here
        )

    [3] => Array
        (
            [question_id] => 2073
            [category_id] => 286
            [question] => Question would appear here
        )

    [4] => Array
            [question_id] => 2029
            [category_id] => 283
            [question] => Question would appear here
        )

    [5] => Array
        (
            [question_id] => 2083
            [category_id] => 287
            [question] => Question would appear here
        )

    [6] => Array
        (
            [question_id] => 2084
            [category_id] => 287
            [question] => Question would appear here
        )

    [7] => Array
        (
            [question_id] => 2036
            [category_id] => 283
            [question] => Question would appear here
        )

    [8] => Array
        (
            [question_id] => 2062
            [category_id] => 285
            [question] => Question would appear here
        )

    [9] => Array
        (
            [question_id] => 2045
            [category_id] => 284
            [question] => Question would appear here
        )

    [10] => Array
        (
            [question_id] => 2052
            [category_id] => 285
            [question] => Question would appear here
        )
)

共有 30 个问题。为了确保均匀分布，两个类别的问题只能比较三次。

如何使用 PHP 构建一个新数组...？

1. 随机问题
2. 将不同类别的问题配对
3. 保险类别仅比较 3 次

--更新--添加 MySQL 表结构，以便更轻松地构建高级查询来执行我正在寻找的操作...

CREATE TABLE `questions` (
  `question_id` int(5) unsigned NOT NULL AUTO_INCREMENT,
  `category_id` int(5) unsigned NOT NULL,
  `question` text NOT NULL,
  PRIMARY KEY (`question_id`),
  UNIQUE KEY `question_id` (`question_id`),
  KEY `questions_ibfk_1` (`category_id`),
  CONSTRAINT `questions_ibfk_1` FOREIGN KEY (`category_id`) REFERENCES `categories` (`category_id`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=latin1;

CREATE TABLE `categories` (
  `category_id` int(5) unsigned NOT NULL AUTO_INCREMENT,
  `category` varchar(64) NOT NULL,
  PRIMARY KEY (`category_id`),
  UNIQUE KEY `category_id` (`category_id`),
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=latin1;

--更新--

我将其作为 MySQL 问题发布，因为我相信构建正确的查询足以满足我的需要。如果您知道如何执行此操作，请发布到以下问题...

How do I build a MySQL query that pulls distinct pairs with a limit on how many times categories can match?

如果您知道通过数组实现此目的的方法，仍然很想知道如何做到这一点。谢谢!

Answer 1

这是我最终想出的有效方法(在尝试构建查询失败后，我需要完成同样的事情)...

原始数组 $theresults 包含来自 5 个不同类别的所有 60 个问题。我首先构建一个包含所有问题类别的数组......

// Create array of all categories
$allcategories = array();
$this->db->select('category_id');
$this->db->where('template_id',$template_id);
$query_thecategories = $this->db->get('categories');
$number_thecategories = $query_thecategories->num_rows();
if ($number_thecategories>0) {
    foreach ($query_thecategories->result() as $row_thecategory) {
        $thecategory = 'cat_' . $row_thecategory->category_id;
        $$thecategory = '0';
        $allcategories[] = $row_thecategory->category_id;
    }
}

然后我使用以下函数来提取类别的所有独特组合...

function array_search_by_key($array, $key, $value) {
    if(!is_array($array)) {
        return [];
    }
    $results = [];
    foreach($array as $element) {
        if(isset($element[$key]) && $element[$key] == $value) {
            $results[] = $element;
        }
    }
    return $results;
}

$uniquecombos = uniquecombos($allcategories, 2);

最后，我循环遍历每个组合，以提取与该对中每个类别匹配的问题，并将结果存储在一个新数组中。 (我循环它三次，因为每个类别配对将使用三次(10 个问题对组合 x 3 个循环 = 60 个问题。)我还删除了从原始 $theresults 数组中提取的每个问题确保没有重复...

// Create an empty array to capture the paired questions
$pairs = array();

// Loop through unique combos array 3 times to build pairings
for($combos = 1; $combos <= 3; $combos++) {
    foreach ($uniquecombos as $theset) {
        // Get two categories in pair
        $firstcategory = $theset[0];
        $secondcategory = $theset[1];

        // Gather other arrays which matches each category
        $matchesfirst = array_search_by_key($theresults,'category_id',$firstcategory);
        shuffle($matchesfirst);
        $matchessecond = array_search_by_key($theresults,'category_id',$secondcategory);
        shuffle($matchessecond);

        // Get question from each new array & add; remove selected question from the original array
        $pairs[] = $matchesfirst[0];
        unset($theresults[$matchesfirst[0]['question_id']]);
        $pairs[] = $matchessecond[0];
        unset($theresults[$matchessecond[0]['question_id']]);
    }
}

希望这对其他人有帮助!