PHP重新排序值

Question

我有一个像这样的数组:

$content = array(array("id_post" => 1000, "id_user" => 4),
                 array("id_post" => 1001, "id_user" => 4),
                 array("id_post" => 1002, "id_user" => 3),
                 array("id_post" => 1003, "id_user" => 4),
                 array("id_post" => 1004, "id_user" => 5),
                 array("id_post" => 1005, "id_user" => 5));

表示5 => 1004, 1005, 4 => 1000, 1001, 1003, 3 => 1002

首先，我如何得到这个结构?(可使用逗号)

对于这个解决方案，我的算法是这样的(这就是我要问你们的……如何实现这一点):

$arr = array();
for($i = 0; $i <= count($content) - 1; $i++){
   if exists key ($content[$i]['id_user']) IN $arr then
      $arr = add_to_existing_key "," . $content[$i]['id_post']
   } other wise {
      $arr = add_new_key PLUS value $content[$i]['id_user'] <=> $content[$i]['id_post']
   }
}

我需要逗号，以便稍后解析信息。基本上，这样做的目的是用$arr变量做一个循环。假设该数组最后有如下内容:

("id_user" => 5, "ids" => '1004,1005'),
("id_user" => 4, "ids" => '1000,1001,1003'),
("id_user" => 3, "ids" => '1002')
for($i = 0; $i <= count($arr) - 1; $i++){
    $ids = explode(",", $arr[$i]['ids']);
    $info = array();
    for($y = 0; $y <= count($ids) - 1; $y++){
        $query->("SELECT * FROM table WHERE id = $ids[$y]");
        $info[] = array($name, $description);
    }
    $email->sendEmail($info); // id = 5 => info OF 1004, 1005
    $info = array();          // clear array
                              // loop
                              // id = 4 => info OF 1000, 1001, 1003
                              // loop etc
}

Answer 1

试试这个:

$arr = array();
// Loop through each content
foreach ($content as $post)
{
  $arr[$post['id_user']][] = $post['id_post'];
}

这样，结果将是

$arr = array(
  '5'=> array('1004', '1005'),
  '4'=> array('1000', '1001', '1003'),
  '3'=> array('1002')
);

那么你就不需要使用" explosion "来分割那些以逗号分隔的id了还

Answer 2

我认为你最好坚持使用数组，而不是用逗号连接，然后再使用exploding:

foreach($content as $values) {
    if(!isset($result[$values['id_user']])) {
        $result[$values['id_user']] = array();
    }
    array_push($result[$values['id_user']], $values['id_post']);
}
print_r($result);

Answer 3

可能这个变体正是您所需要的:

$content = array(array("id_post" => 1000, "id_user" => 4),
    array("id_post" => 1002, "id_user" => 3),
    array("id_post" => 1004, "id_user" => 5),
    array("id_post" => 1003, "id_user" => 4),
    array("id_post" => 1001, "id_user" => 4),
    array("id_post" => 1005, "id_user" => 5));
// Make preparation array
foreach ( $content as $values ) {
    if ( !isset($result[$values['id_user']]) ) {
        $result[$values['id_user']] = array();
    }
    array_push($result[$values['id_user']], $values['id_post']);
}
// Sort inner arrays
foreach ( $result as $key => $valueArray ) {
    asort($result[$key]);
}
// Implode arrays to strings
array_walk($result, function(&$array, $key) {
            $array = implode(',', $array);
        });
// Final array
$result1 = array();
foreach ( $result as $userID => $idsString ) {
    $result1[] = array("id_user" => $userID, "id_post" => $idsString);
}
print_r($result1);