如何使用其键将数组分组为子数组？

Question

我希望根据其键将数组分组为子数组。

样本数组

Array
(
    [0] => Array
        (
            [a_id] => 1
            [a_name] => A1
            [b_id] => 1
            [b_name] => B1
            [c_id] => 1
            [c_name] => C1
        )

    [1] => Array
        (
            [a_id] => 1
            [a_name] => A1
            [b_id] => 1
            [b_name] => B1
            [c_id] => 2
            [c_name] => C2
        )

    [2] => Array
        (
            [a_id] => 1
            [a_name] => A1
            [b_id] => 2
            [b_name] => B2
            [c_id] => 3
            [c_name] => C3
        )

    [3] => Array
        (
            [a_id] => 2
            [a_name] => A2
            [b_id] => 3
            [b_name] => B3
            [c_id] => 4
            [c_name] => C4
        )

)

我需要将此示例数组转换为以下格式的 JSON 数组：

预期输出

[{
    "a_id": 1,
    "a_name": "A1",
    "b_list": [{
        "b_id": 1,
        "b_name": "B1",
        "c_list": [{
            "c_id": 1,
            "c_name": "C1"
        }, {
            "c_id": 2,
            "c_name": "C2"
        }]
    }, {
        "b_id": 2,
        "b_name": "B2",
        "c_list": [{
            "c_id": 3,
            "c_name": "C3"
        }]
    }]
}, {
    "a_id": 2,
    "a_name": "A2",
    "b_list": [{
        "b_id": 3,
        "b_name": "B3",
        "c_list": [{
            "c_id": 4,
            "c_name": "C4"
        }]
    }]
}]

我可以使用下面的代码按一个键进行分组。

$array = array(
array("a_id" => "1","a_name" => "A1","b_id" => "1","b_name" => "B1","c_id" => "1","c_name" => "C1"),
array("a_id" => "1","a_name" => "A1","b_id" => "1","b_name" => "B1","c_id" => "2","c_name" => "C2"),
array("a_id" => "1","a_name" => "A1","b_id" => "2","b_name" => "B2","c_id" => "3","c_name" => "C3"),
array("a_id" => "2","a_name" => "A2","b_id" => "3","b_name" => "B3","c_id" => "4","c_name" => "C4")
);
$return = array();
foreach($array as $val) {
    $return[$val["a_id"]][] = $val;
}
print_r($return);

但是我的实际场景涉及到分组到子数组中并没有奏效。

期待看看是否有优化的方式或有用的功能可以进入我预期的 JSON 响应。

注意：我在这里研究一个通用的用例。例如：a_list 代表国家，b_list 代表州，c_list 代表城市。

Answer 1

这是一个非常具体的数组用例。那么这是你的解决方案。

$array = <YOUR SAMPLE ARRAY>
$output = [];
/*
 * Nesting array based on a_id, b_id
 */
foreach ($array as $item) {
    $aid = $item['a_id'];
    $bid = $item['b_id'];
    $cid = $item['c_id'];
    if(!isset($output[$aid])){
        $output[$aid] = [
            'a_id' => $item['a_id'],
            'a_name' => $item['a_name'],
            'b_list' => [
                $bid => [
                    'b_id' => $item['b_id'],
                    'b_name' => $item['b_name'],
                    'c_list' => [
                        $cid = [
                            'c_id' => $item['c_id'],
                            'c_name' => $item['c_name']
                        ]
                    ]
                ]
            ]
        ];
    } else if (!isset($output[$aid]['b_list'][$bid])){
        $output[$aid]['b_list'][$bid] =  [
            'b_id' => $item['b_id'],
            'b_name' => $item['b_name'],
            'c_list' => [
                $cid => [
                    'c_id' => $item['c_id'],
                    'c_name' => $item['c_name']
                ]
            ]
        ];
    } else if(!isset($output[$aid]['b_list'][$bid]['c_list'][$cid])) {
        $output[$aid]['b_list'][$bid]['c_list'][$cid] = [
            'c_id' => $item['c_id'],
            'c_name' => $item['c_name']
        ];
    } else {
        // Do/Dont overrider
    }
}
/*
 * Removing the associativity from the b_list and c_list
 */
function indexed($input){

    $output = [];
    foreach ($input as $key => $item) {
        if(is_array($item)){
            if($key == 'b_list' || $key == 'c_list'){
                $output[$key] = indexed($item);
            } else {
                $output[] = indexed($item);
            }
        } else {
            $output[$key] = $item;
        }
    }
    return $output;
}
$indexed = indexed($output);
print_r(json_encode($indexed, 128));

Answer 2

那里有有趣的要求。 这是我的通用解决方案，也是可扩展的。

function transform($array, $group=[
    ['a_id','a_name','b_list'],
    ['b_id','b_name','c_list'],
    ['c_id','c_name'],
]){
    foreach($array as $a){
        $r = &$result;
        foreach($group as $g){
            $x = &$r[$a[$g[0]]];
            $x[$g[0]] = $a[$g[0]];
            $x[$g[1]] = $a[$g[1]];
            if(isset($g[2])) $r = &$x[$g[2]]; else break;
        }
    }
    return transformResult($result);
}

function transformResult($result){
    foreach($result as &$a)
        foreach($a as &$b)
            if(is_array($b)) $b = transformResult($b);
    return array_values($result);
}

要扩展这个解决方案，你所要做的就是修改$group参数， 直接在函数声明中或通过将适当的值作为第二个参数传递。

使用示例：

echo json_encode(transform($array), JSON_PRETTY_PRINT);

假设您的示例中输入相同的$array，这将返回相同的输出。

Answer 3

现在这里是在给定情况下效果最好的代码。我创造了一个类似的情况，然后详细解释了解决方案。

情况
订单是多页的，具体取决于所选包裹的服务天数。每个包裹的详细信息都存储在数据库中，包含以下字段：

1. package_id（唯一字段）
2. package_name（包的名称，例如包 A）
3. servings_count（一天的总份数）
4. days_served（一个月的服务天数）

为了将每天的膳食选择和当天的服务作为订单存储在数据库中，我需要一个可以动态定义/填充的 PHP 多维数组。

预期的输出类似于：

Array
(
    [Day 1] => Array
        (
            [meal_id_1] => Unique ID //to be replaced with user selection
            [meal_code_1] => Meal Name //to be replaced with user selection
            [meal_type_1] => Meal //prefilled based on the selected package
            [meal_id_2] => Not Available //to be replaced with user selection
            [meal_code_2] => 2 //to be replaced with user selection
            [meal_type_2] => Meal //prefilled based on the selected package
        )

    [Day 2] => Array
        (
            [meal_id_1] => Unique ID //to be replaced with user selection
            [meal_code_1] => Meal Name //to be replaced with user selection
            [meal_type_1] => Meal //prefilled based on the selected package
            [meal_id_2] => Not Available //to be replaced with user selection
            [meal_code_2] => 2 //to be replaced with user selection
            [meal_type_2] => Meal //prefilled based on the selected package
        )

上述数组是根据解释的结构和份数和天数 100% 动态创建的。下面是一些解释的代码。

首先，我们必须声明两个 PHP 数组。

$total_meals_array = []; //Primary, Multidimension Array
$meals_selected_array = []; //Meals Details Array to be used as primary array's key value.

完成此操作后，运行 MySQL 查询以从数据库中读取包。现在根据结果，执行以下操作：

$total_meals_array = []; //Primary, Multidimension Array
$meals_selected_array = []; //Meals Details Array to be used as primary array's key value.

if( $num_row_packages >= 1 ) {
    while($row_packages = mysqli_fetch_array ($result_packages)) {
        $package_id = $row_packages['package_id'];
        $package_name = $row_packages['package_name'];
        $servings_count = $row_packages['servings_count'];
        $days_served = $row_packages['days_served'];

        //this for loop is to repeat the code inside `$days_served` number of times. This will be defining our primary and main Multidimensional Array `$total_meals_array`.
        for ($y = 1; $y <= $days_served; $y++) {
            //once inside the code, now is the time to define/populate our secondary array that will be used as primary array's key value. `$i`, which is the meal count of each day, will be added to the key name to make it easier to read it later. This will be repeated `$meals_count` times.

            for ($i = 1; $i <= $meals_count; $i++) {
                $meals_selected_array["meal_id_" . $i] = "Unique ID";
                $meals_selected_array["meal_code_" . $i] = "Meal Name";
                $meals_selected_array["meal_type_" . $i] = "Meal";
            }

            //once our secondary array, which will be used as the primary array's key value, is ready, we will start defining/populating our Primary Multidimensional Array with Keys Named based on `$days_served`.
            $total_meals_array["Day " . $y] = $meals_selected_array;
        }
    }
}

就是这样！我们的动态多维数组已经准备好了，可以通过以下代码查看：

print "<pre>";
print_r($total_meals_array);
print "</pre>";

谢谢大家，特别是@yarwest 好心回答我的问题。

Answer 4

这是代码，您可以将其用于从 a_ 到 y_ 深度的索引。如果你不想要它，最里面的元素是空的。在最后一个元素之前终止 for 循环，然后单独处理最后一个元素。您还可以对此代码进行一些改进。希望这会有所帮助。

 <?php
    $array = array(
    array("a_id" => "1","a_name" => "A1","b_id" => "1","b_name" => "B1","c_id" => "1","c_name" => "C1"),
    array("a_id" => "1","a_name" => "A1","b_id" => "1","b_name" => "B1","c_id" => "2","c_name" => "C2"),
    array("a_id" => "1","a_name" => "A1","b_id" => "2","b_name" => "B2","c_id" => "3","c_name" => "C3"),
    array("a_id" => "2","a_name" => "A2","b_id" => "3","b_name" => "B3","c_id" => "4","c_name" => "C4")
    );
    $arrays = array_map(function($v){return array_chunk($v, 2, true);}, $array);
    $result = [];
    foreach($arrays as $value)
    {
        $ref = &$result;
        $len = count($value);
        $index = 0;
        for(; $index < $len; $index++)
        {
            $arr = $value[$index];
            $char = key($arr)[0];
            $charAdd = chr(ord($char)+1);
            $key = $arr[$char.'_id'].$arr[$char.'_name'];
            $listKey = $charAdd.'_list';
            foreach($arr as $k => $v)
            {
                $ref[$key][$k] = $v;
            }
            $ref = &$ref[$key][$listKey];
        }
    }
    var_dump($result);

输出：在线live demo

ei@localhost:~$ php test.php
array(2) {
  ["1A1"]=>
  array(3) {
    ["a_id"]=>
    string(1) "1"
    ["a_name"]=>
    string(2) "A1"
    ["b_list"]=>
    array(2) {
      ["1B1"]=>
      array(3) {
        ["b_id"]=>
        string(1) "1"
        ["b_name"]=>
        string(2) "B1"
        ["c_list"]=>
        array(2) {
          ["1C1"]=>
          array(3) {
            ["c_id"]=>
            string(1) "1"
            ["c_name"]=>
            string(2) "C1"
            ["d_list"]=>
            NULL
          }
          ["2C2"]=>
          array(3) {
            ["c_id"]=>
            string(1) "2"
            ["c_name"]=>
            string(2) "C2"
            ["d_list"]=>
            NULL
          }
        }
      }
      ["2B2"]=>
      array(3) {
        ["b_id"]=>
        string(1) "2"
        ["b_name"]=>
        string(2) "B2"
        ["c_list"]=>
        array(1) {
          ["3C3"]=>
          array(3) {
            ["c_id"]=>
            string(1) "3"
            ["c_name"]=>
            string(2) "C3"
            ["d_list"]=>
            NULL
          }
        }
      }
    }
  }
  ["2A2"]=>
  array(3) {
    ["a_id"]=>
    string(1) "2"
    ["a_name"]=>
    string(2) "A2"
    ["b_list"]=>
    array(1) {
      ["3B3"]=>
      array(3) {
        ["b_id"]=>
        string(1) "3"
        ["b_name"]=>
        string(2) "B3"
        ["c_list"]=>
        array(1) {
          ["4C4"]=>
          array(3) {
            ["c_id"]=>
            string(1) "4"
            ["c_name"]=>
            string(2) "C4"
            ["d_list"]=>
            &NULL
          }
        }
      }
    }
  }
}

Answer 5

这很有趣。据我所知，您正在尝试将平面数组转换为多维数组，以及将 keys 转换为多维表示。

顶级差异似乎存在于a_* 键的下划线之前的部分。

然后，对于这些键中的每一个，每隔一个*_ 字母应该会产生它自己的列表。

此递归函数无需硬编码即可解决问题，适用于任意数量的级别、字母（或其他任何内容）和正确的标识符。

它似乎完全返回了您在示例中显示的 json（$array 是您问题中定义的数组）

$multidimension = multidimensionalify($array, ['a', 'b', 'c'], ['name']);
var_dump(json_encode($multidimension, JSON_PRETTY_PRINT));

function multidimensionalify(
    array $input,
    array $topLevelLetters,
    array $rightHandIdentifiers,
    $level = 0,
    $parentId = null,
    $uniqueString = 'id'
)
{
    $thisDimension = [];
    $thisLetter = $topLevelLetters[$level];
    foreach ($input as $entry)
    {
        $thisId = $entry["{$thisLetter}_{$uniqueString}"];
        $condition = true;
        if ($parentId !== null)
        {
            $parentLetter = $topLevelLetters[$level - 1];
            $condition = $entry["{$parentLetter}_{$uniqueString}"] === $parentId;
        }
        if (!isset($thisDimension[$thisId]) && $condition)
        {
            $thisObject = new stdClass;
            $thisObject->{"{$thisLetter}_{$uniqueString}"} = $thisId;
            foreach ($rightHandIdentifiers as $identifier)
            {
                $thisObject->{"{$thisLetter}_{$identifier}"} = $entry["{$thisLetter}_{$identifier}"];
            }
            if (isset($topLevelLetters[$level + 1])) {
                $nextLetter = $topLevelLetters[$level + 1];
                $thisObject->{"{$nextLetter}_list"} = multidimensionalify($input, $topLevelLetters, $rightHandIdentifiers, $level + 1, $thisId, $uniqueString);
            }
            $thisDimension[$thisId] = $thisObject;
        }
    }
    return array_values($thisDimension);
}

Answer 6

试试这个函数，只需传递你的数组和键名进行分组，然后转换为 json。

public function _group_by($array, $key) {
    $return = array();
    foreach ($array as $val) {
        $return[$val[$key]][] = $val;
    }
    return $return;
}