对php中的数组进行分组并计数数据

Question

最近，我正在做一个项目，根据'Franchaise‘和’超级大国‘的起源，把’超级英雄‘和’超级恶棍‘分类。我希望以数组#1的形式从数据库中获取数据，并在php中将它们显示为Array #2。

 Array #1

Array
(
  [0] => Array
    (
      [id] => 101
      [Name] => Superman
      [Franchise] => DC Comics
      [Superpower] => Inherent
    )

  [1] => Array
    (
      [id] => 908
      [Name] => Batman
      [Franchise] => DC Comics
      [Superpower] => Acquired
    )

  [2] => Array
    (
      [id] => 228
      [Name] => Wolverine
      [Franchise] => Marvel
      [Superpower] => Acquired
    )

  [3] => Array
    (
      [id] => 158
      [Name] => Iron Man
      [Franchise] => Marvel
      [Superpower] => Acquired
    )

  [4] => Array
    (
      [id] => 978
      [Name] => Thor
      [Franchise] => Marvel
      [Superpower] => Inherent
    )
)

数组#1元素必须根据它们的“专营权”进行分组，并以“超能力”来计算其中有多少是“固有的”或“获得的”。

Array #2


Array
(
  [DC Comics] => Array
    (
      [Inherent] => 1
      [Acquired] => 1
    )

  [Marvel] => Array
    (
      [Inherent] => 1
      [Acquired] => 2
    )
)

Answer 1

下面是没有太多逻辑的代码，

foreach ($array1 as $val) {
    if(!isset($array2[$val['Franchise']])) {
       $array2[$val['Franchise']] = array('Inherent' => 0, 'Acquired' => 0);
    }
    $array2[$val['Franchise']][$val['Superpower']]++;
}

print_r($array2);

Answer 2

1. array_column()函数从2D数组聚合内部键。
2. array_count_values()函数对数组的所有值进行计数。

对计数值使用此代码段：

$a = array ( array ("id" => "101", "Name" => "Superman", "Franchise" => "DC Comics", "Superpower" => "Inherent" ),
   array ( "id" => "908", "Name" => "Batman", "Franchise" => "DC Comics", "Superpower" => "Acquired" ),
   array ( "id" => "228", "Name" => "Wolverine", "Franchise" => "Marvel", "Superpower" => "Acquired" ),
   array ( "id" => "158", "Name" => "Iron Man", "Franchise" => "Marvel", "Superpower" => "Acquired" ),
   array ( "id" => "978", "Name" => "Thor", "Franchise" => "Marvel", "Superpower" => "Inherent" ));
  echo "<pre>";
$return = array();
// first group array values by franchise
foreach($a as $val) {
    if (!isset($return[$val['Franchise']])) {
        $return[$val['Franchise']] = array();
    }
    $return[$val['Franchise']][] = $val;
}
$arr = array();
// count elements by key value pair in particular franchise
foreach ($return as $key => $value) {
    $tmp = array_count_values(array_column($value, 'Superpower'));
    $arr[$key] = $tmp;
}
print_r($arr);

演示在这里

Answer 3

具有单一和短的http://php.net/manual/en/function.array-reduce.php

// $arr is your initial array
$result = array_reduce($arr, function($r, $v){
    if (isset($r[$v["Franchise"]][$v["Superpower"]])) {
        $r[$v["Franchise"]][$v["Superpower"]] += $r[$v["Franchise"]][$v["Superpower"]];
    } else {
        $r[$v["Franchise"]][$v["Superpower"]] = 1;
    }
    return $r;
}, []);

print_r($result);

产出：

Array
(
    [DC Comics] => Array
        (
            [Inherent] => 1
            [Acquired] => 1
        )

    [Marvel] => Array
        (
            [Acquired] => 2
            [Inherent] => 1
        )
)