如何合併兩個數組的值？

Question

我有兩個數組：

$a = array(
    array("id" => 132), 
    array("id" => 131), 
    array("id" => 129), 
    array("id" => 128) 
) 

$b = array(
    array("id" => 129, "attachment_id" => 111), 
    array("id" => 129, "attachment_id" => 112), 
    array("id" => 132, "attachment_id" => 113), 
    array("id" => 132, "attachment_id" => 114), 
    array("id" => 132, "attachment_id" => 115) 
) 

我需要從這兩個一個陣列。 id鍵必須是唯一的，所以不能重複。問題是：我需要在該新陣列中創建一個名爲attachments的新元素，該元素是數組，並且包含id的attachment_id的值。你看，可能有更多的attachment_idid。

很難解釋，但我希望你能理解！謝謝你的建議。

編輯：

這裏是理想的結果：

$c = array(
    array("id" => 132, 'attachments' => array(113, 114, 115)), 
    array("id" => 131, 'attachments' => array()), 
    array("id" => 129, 'attachments' => array(111, 112)), 
    array("id" => 128, 'attachments' => array()) 
); 

Answer 1

喜歡的東西：

$a = array(
    array("id" => 132), 
    array("id" => 131), 
    array("id" => 129), 
    array("id" => 128) 
); 

$b = array(
    array("id" => 129, "attachment_id" => 111), 
    array("id" => 129, "attachment_id" => 112), 
    array("id" => 132, "attachment_id" => 113), 
    array("id" => 132, "attachment_id" => 114), 
    array("id" => 132, "attachment_id" => 115) 
); 

$c = array(); 

foreach ($a as $idEntry) { 
    $tmp = array(
     'id' => $idEntry['id'], 
     'attachments' => array() 
    ); 

    foreach ($b as $bIdx => $attachmentEntry) { 
     if ($attachmentEntry['id'] == $idEntry['id']) { 
      $tmp['attachments'][] = $attachmentEntry['attachment_id']; 
      unset($b[$bIdx]); 
     } 
    } 

    $c[] = $tmp; 
} 

print_r($c); 

Answer 2

指數的陣列，由 'ID'，然後使用http://php.net/manual/en/function.array-merge.php

Answer 3

像這樣的東西應該這樣做：

# Temporary array 
$c = array(); 

# Loop through all attachments and index them by id 
foreach($b as $row) { 
    if(!isset($c[$row['id']])) { 
     $c[$row['id']] = array(); 
    } 
    $c[$row['id']][] = $row['attachment_id']; 
} 

# Loop through ids and add attachments where available 
foreach($a as &$row) { 
    $row['attachments'] = isset($c[$row['id']]) ? $c[$row['id']] : array() 
} unset($row); 

輸出：

array(
    array("id" => 132, "attachments" => array(113, 114, 115)), 
    array("id" => 131, "attachments" => array()), 
    array("id" => 129, "attachments" => array(111, 112)), 
    array("id" => 128, "attachments" => array()) 
)