如何同時匹配在PHP多維數組的另一個關鍵值

Question

我有如下一個多維數組總和鍵值：

array 
(
    0 => array("id" => 4, "price" => 1000), 
    1 => array("id" => 4, "price" => 500), 
    2 => array("id" => 5, "price" => 1000), 
    3 => array("id" => 5, "price" => 1000), 
    4 => array("id" => 4, "price" => 0), 
    5 => array("id" => 5, "price" => 0) 
) 

而想要合成陣列象下面這樣：

array 
(
    0 => array("id" => 4, "price" => 1500), 
    1 => array("id" => 5, "price" => 2000), 
) 

是那些價格匹配id的總和，例如。 id = 4價格將是結果數組中的（1000 + 500 + 0）之和。

如何在PHP中得到結果數組？

Answer 1

使用此：

$aggregated = []; 

foreach ($rows as $row) { 
    $id = $row['id']; 
    $price = $row['price']; 

    if (!array_key_exists($id, $aggregated)) { 
     $aggregated[$id] = [ 
      'id' => $id, 
      'price' => $price, 
     ]; 

     continue; 
    } 

    $aggregated[$id]['price'] += $price; 
} 

$result = array_values($aggregated); 

對於裁判erence，參見：

• http://php.net/manual/en/function.array-key-exists.php
• http://php.net/manual/en/control-structures.continue.php
• http://php.net/manual/en/function.array-values.php

有關示例，請參見：

• https://3v4l.org/ctgD9

Answer 2

我編輯答案補充一條線，將刪除錯誤通知

循環用foreach和使用加法。

$arr = array 
(
    0 => array("id" => 4, "price" => 1000), 
    1 => array("id" => 4, "price" => 500), 
    2 => array("id" => 5, "price" => 1000), 
    3 => array("id" => 5, "price" => 1000), 
    4 => array("id" => 4, "price" => 0), 
    5 => array("id" => 5, "price" => 0) 
); 

$result = array(); 
foreach($arr as $val){ 
    if(!isset($result[$val["id"]])) $result[$val["id"]] =0; 
    $result[$val["id"]] += $val["price"]; 
} 

var_dump($result); 

https://3v4l.org/2D5Ei

Answer 3

有了簡單foreach：

$arr = array 
    (
    0 => array("id" => 4, "price" => 1000), 
    1 => array("id" => 4, "price" => 500), 
    2 => array("id" => 5, "price" => 1000), 
    3 => array("id" => 5, "price" => 1000), 
    4 => array("id" => 4, "price" => 0), 
    5 => array("id" => 5, "price" => 0) 
); 

$sum = []; 
foreach ($arr as $value) { 
    extract($value); 
    $sum[$id]['id'] = $id; 
    if (array_key_exists($id, $sum)) { 
     $sum[$id]['price'] = $price; 
    } else { 
     $sum[$id]['price'] += $price; 
    } 
} 

print_r(array_values($sum)); 

Demo