PHP对两个多维数组的元素求和

Question

这是我在 StackOverflow 上的第一篇文章。

我正在寻找最好的方法来获取两个数组，每个数组都有不同数量的数据项，将它们合并，但将其中一个键上具有相同值的项相加（使用 PHP）。

输入数组：

$array1 = array ( 
    0 => array ( 'result_date' => '2020-07-20', 'total_for_day' => '75', ), 
    1 => array ( 'result_date' => '2020-07-21', 'total_for_day' => '17', ), 
    2 => array ( 'result_date' => '2020-07-22', 'total_for_day' => '0', ), 
    3 => array ( 'result_date' => '2020-07-23', 'total_for_day' => '6', ), 
    4 => array ( 'result_date' => '2020-07-24', 'total_for_day' => '1', )
);
$array2 = array ( 
    0 => array ( 'result_date' => '2020-07-01', 'total_for_day' => '6264', ), 
    1 => array ( 'result_date' => '2020-07-02', 'total_for_day' => '7008', ), 
    2 => array ( 'result_date' => '2020-07-20', 'total_for_day' => '1968', ), 
    3 => array ( 'result_date' => '2020-07-21', 'total_for_day' => '7776', ), 
);

期望的输出：

array ( 
    0 => array ( 'result_date' => '2020-07-01', 'total_for_day' => '6264', ), 
    1 => array ( 'result_date' => '2020-07-02', 'total_for_day' => '7008', ), 
    2 => array ( 'result_date' => '2020-07-20', 'total_for_day' => '2043', ), 
    3 => array ( 'result_date' => '2020-07-21', 'total_for_day' => '7793', ), 
    4 => array ( 'result_date' => '2020-07-22', 'total_for_day' => '0', ), 
    5 => array ( 'result_date' => '2020-07-23', 'total_for_day' => '6', ), 
    6 => array ( 'result_date' => '2020-07-24', 'total_for_day' => '1', )
);

所以基本上只是将两个数组合并为一个更大的数组，但将“result_date”匹配的“total_for_day”相加。请注意，在所需的输出中，它也由“result_date”ASC 排序。

提前致谢:-)

Answer 1

我会采用简单的方法并使用中间数组映射：

$array1 = array(...);
$array2 = array(...);
$arrayN = array(...);

$merged = array();
foreach (array_merge($array1, $array2, $arrayN) as $record) {
    $date = $record["result_date"];
    if (!isset($merged[$date])) {
        $merged[$date] = 0;
    }
    $merged[$date] += $record["total_for_day"];
}

$result = array();
foreach ($merged as $date => $days) {
    $result[] = array(
        "result_date" => $date, 
        "total_for_day" => "{$days}" // Remove the quotes if you don't want a string.
    );
}

usort($result, function ($a, $b) {
    return $a["result_date"] <=> $b["result_date"];
});

var_dump($result);