如何重建沒有重復和其他限制的數組？

Question

我有一個應用程序，允許人們提供自定義評估。 我根據客戶的要求建立了一個新的評分機制，允許參與者根據哪個更准確地選擇兩個問題。 問題是我需要隨機化問題，確保來自同一類別的兩個問題不會一起出現，並限制它，因此來自相同兩個類別的兩個問題僅進行三次比較。

我試圖在這里修改其他問題的代碼/答案，但沒有一個直接適用，我很難適應最接近的問題。

這是我原始數組中包含問題的樣本（已經隨機化，但沒有其他標准）......

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
        )
)

總共有30個問題。 為了確保均勻分布，兩個類別的問題只應進行三次比較。

如何使用PHP構建一個新數組...？

1. 隨機化問題
2. 對不同類別之間的問題
3. 保險類別僅進行三次比較

--UPDATE--添加MySQL表結構，以防更容易構建高級查詢來執行我正在尋找的...

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;

--UPDATE--

我將此作為MySQL問題發布，因為我相信構建正確的查詢就足以滿足我的需求。 如果您對如何操作有所了解，請發布以下問題...

如何構建一個MySQL查詢來提取不同的對，並限制類別可以匹配的次數？

如果您知道通過數組實現此目的的方法，仍然會想知道如何這樣做。 謝謝！

Answer 1

這是我最終提出的工作（嘗試構建查詢失敗后我需要完成相同的事情）...

原始數組$theresults包含來自5個不同類別的所有60個問題。 我首先構建一個包含所有問題類別的數組......

// 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;
    }
}

然后我使用以下函數來拉出所有類別的獨特組合......

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，我遍歷每個組合以提取與該對中的每個類別匹配的問題，並將結果存儲在新數組中。 （我循環三次，因為每個類別配對將使用三次（問題對的10個組合x 3個循環= 60個問題。）我還刪除了我從原始$theresults數組中提取的每個問題，以確保沒有重復... 。

// 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']]);
    }
}

希望這有助於其他人！