通过二级键对二维数组的关联元素进行分组并对共享键的值求和[重复]

Question

我有一个包含子数组的数组。我想对键相同的值求和并将其放入一个列表中。

这是我的数组：

$array = [ 
    ['x1' => 1, 'x2' => 3, 'y5' => 9],
    ['x1' => 3, 'x4' => 1, 'y5' => 1],
    ['x1' => 1, 'x8' => 5, 'a5' => 2],
    ['x1' => 2, 'x10' => 3, 'b5' => 5],
];

我想要一个像这样的数组：

$newarray = [
    'x1' => 7,
    'x2' => 3,
    'x4' => 1,
    'x8' => 5,
    'x10' => 3,
    'y5' => 9,
    'y5' => 1,
    'a5' => 2
];

我的尝试：

foreach ($array as $key => $values) {
    foreach ($values as $n_k => $n_v) { 
        $newarray[$n_k] += $n_v;
    }
}

Answer 1

问题是您正在添加一个值，即使它没有定义。

您可以检查是否未设置并将值初始化为

0

if ( !isset($newarray[$n_k]) ) $newarray[$n_k] = 0;

完整代码如下：

$array =  array( array('x1'=> 1, 'x2' => 3, 'y5' => 9), array('x1'=> 3, 'x4' => 1, 'y5' => 1), array('x1'=> 1, 'x8' => 5, 'a5' => 2), array('x1'=> 2, 'x10' => 3, 'b5' => 5));
$newarray = array();

foreach($array as $key => $values){
   foreach($values as $n_k => $n_v) {   
       if ( !isset($newarray[$n_k]) ) $newarray[$n_k] = 0;
       $newarray[$n_k] += $n_v;
   }
}

这将导致：

Array
(
    [x1] => 7
    [x2] => 3
    [y5] => 10
    [x4] => 1
    [x8] => 5
    [a5] => 2
    [x10] => 3
    [b5] => 5
)

Answer 2

您可以首先从数组中获取所有键，然后在 array_column 和 array_sum 中使用它来获得所需的输出。
如果数组更大，这可能会带来更多好处。

$array =  array( array("x1" => 1, "x2" => 3, "y5" => 9),
                 array("x1" => 3, "x4" => 1, "y5" => 1),
                 array("x1" => 1, "x8" => 5, "a5" => 2),
                 array("x1" => 2, "x10" => 3, "b5" => 5)
                );

$keys = [];
// get all keys used in $array
foreach($array as $subarr){
     $keys = array_merge($keys, array_keys($subarr));
}
// $keys is now: 
// array (0 => 'x1', 1 => 'x2', 2 => 'y5', 3 => 'x1', 4 => 'x4', 5 => 'y5', 6 => 'x1', 7 => 'x8', 8 => 'a5', 9 => 'x1', 10 => 'x10', 11 => 'b5')

// loop only unique keys and sum the values
foreach(array_unique($keys) as $item){
    $res[$item] = array_sum(array_column($array, $item));
}
var_dump($res);

https://3v4l.org/WaqlG

Answer 3

这不是我的问题，但我发现这个可以帮助你：

https://stackoverflow.com/a/14196064/9721446

您必须创建一个新数组，然后对于每个相等的 keyid，您将添加该值。类似这样的想法我认为它有效。 如果没有帮助你，看看这篇文章，那也不是我的！！！！

关联数组，相同key的值求和

Answer 4

 $input =  array( array(x1=> 1, x2 => 3, y5 => 9),
 array(x1=> 3, x4 => 1, y5 => 1),
 array(x1=> 1, x8 => 5, a5 => 2),
 array(x1=> 2, x10 => 3)
);
 $final = array();
 array_walk_recursive($input, function($item, $key) use (&$final){
     $final[$key] = isset($final[$key]) ?  $item + $final[$key] : $item;
 });
  print_r($final);