想不通

Question

好的，我们开始吧..

假设$topic['is_new'] 由“7325823”组成，accID 为 63426，然后它会更新为 7325823|63426，但如果我再次重新加载页面，它会删除 7325823|所以它只有 63426。我不想要那个。

怎么了？想不通

$accID = userid goes here;

$topic['is_new'] = "72482|81249|8124|42534|...and so on"; // user ids that i get from field in topics table
$list_of_ids = explode('|', $topic['is_new']); 

// lets see if the user has already been here
if (!in_array($accID, $list_of_ids)) {
$in = isset($topic['is_new']) && !in_array($accID, $list_of_ids) ?    $topic['is_new'].'|'.$accID : $topic['is_new'].'|'.$accID; 
} else {
// if he havent, add him to the list
$in = $accID;
}

// yes i know, PDO is better
mysqli_query("UPDATE topics
   SET num_views = num_views+1, is_new = '$in'
   WHERE id = $tid") or die(mysqli_error($link));

这就是我想要实现的：custom php forum - showing new/unread posts

Answer 1

您的“将他添加到列表”代码会用新的用户 ID 覆盖列表，而不是附加到列表中。此外，代码的“查看用户是否已经到过这里”的形式是“如果 X 则 Y 否则 Y”。

试试这样的：

$list_of_ids = $topic['is_new'] ? explode("|",$topic['is_new']) : array();
// above code ensures that we get an empty array instead of
//                              an array with "" when there are no IDS
if( !in_array($accID,$list_of_ids)) $list_of_ids[] = $accID;

$newIDstring = implode("|",$list_of_ids);
// do something with it.

也就是说，你正在做的是一个非常糟糕的主意。不过，如果不了解您的项目，我真的无法告诉您什么是好主意。

Answer 2

您的问题在您的 if 语句中：

// lets see if the user has already been here
if (!in_array($accID, $list_of_ids)) {
    //if the user is not in the array, they are added here
    //your if here was returnign the same thing either way, so simplify
    $in = $topic['is_new'].'|'.$accID; 
} else {
    //HERE is your problem ... 
    //if the user is found in the array, you set $in to just the account id and update the database ... 
    //I would think you would not want to do anything here ... 
    //so comment out the next line
    //$in = $accID;
}

Answer 3

这让我大吃一惊，也许是故意的。

$in = isset($topic['is_new']) && !in_array($accID, $list_of_ids) ?    $topic['is_new'].'|'.$accID : $topic['is_new'].'|'.$accID; 

结果是一样的：

? $topic['is_new'].'|'.$accID
: $topic['is_new'].'|'.$accID

这里的下一个（或主要）问题，你 else 需要工作。

考虑这个流程：

$topic['is_new'] = '7325823';
$list_of_ids would contain 7325823
!in_array() so it appends it

刷新页面：

$topic['is_new'] = '7325823|63426';
$list_of_ids would contain 7325823, 63326
in_array() === true so $in = $accID

主题更新为 63426？