Foreach循环和阵列构建

Question

我有一个管理区域，他们可以在那里一次删除多个用户。这是处理删除的代码的一部分。基本上，它会遍历用户id并删除每个标记为已检查的用户id。

if ($_POST['doDelete'] == 'Delete') {
    if (!empty($_POST['u'])) {
        foreach ($_POST['u'] as $uid) {
            $id = escape($uid);
            $delete = Nemesis::query("DELETE FROM users WHERE id = '{$id}' AND id <> '{$_SESSION[user_id]}'");
            if (!$delete) {
                $msg->add('e', QUERY_ERROR);
                redirect('users.php');
                exit();
            }
        }
    }
    /* we need a way to iterate over users deleted */
    $msg = new Messages();
    $msg->add('s', QUERY_DELETE_SUCCESS);
    redirect('users.php');
    exit();
}
function get_user_name_from_id($user_id)
{
    if ($_SESSION['user_level'] == ADMIN_LEVEL) {
        $viewUserMod = 1;
    } else {
        $config = Nemesis::select("usr_view_cm", "config");
        $row_config = $config->fetch_assoc();
        $viewUserMod = $row_config['usr_view_cm'];
    }
    if (is_numeric($user_id) && $viewUserMod == 1) {
        $sql = Nemesis::select("full_name", "users", "id = {$user_id}");
        if ($sql->num_rows > 0) {
            $user_name = $sql->fetch_assoc();
            return $user_name['full_name'];
        } else {
            // user name cannot be matched with db, either error, or most likely user was deleted
            return 'User ' . $user_id;
        }
    } else {
        return $user_id;
    }
}

在它说QUERY_DELETE_SUCCESS的地方，我想输出类似于"Deleted Bob，Jack，Tim"等的内容。我有一个函数，它使用用户id并获取他们的姓名。问题是一旦迭代完成。显然，那些用户在数据库中已不存在，我无法获取他们的姓名有没有办法在循环中运行这个函数，并构建一个字符串或数组。可以代替消息输出吗

Answer 1

您应该能够做到这一点：

if ($_POST['doDelete'] == 'Delete') {
    $deleted = array();
    if (!empty($_POST['u'])) {
        foreach ($_POST['u'] as $uid) {
            $id = escape($uid);
            $username = get_user_name_from_id($uid);
            $delete = Nemesis::query("DELETE FROM users WHERE id = '{$id}' AND id <> '{$_SESSION[user_id]}'");
            if (!$delete) {
                $msg->add('e', QUERY_ERROR);
                redirect('users.php');
                exit();
            }
            $deleted[] = $username // push name to array after deletion is successful
        }
    }
    /* The $deleted array now holds the names of the deleted users.
     * Do with it what you want.
     */
    $names = implode(",", $deleted)
    $msg = new Messages();
    $msg->add('s', QUERY_DELETE_SUCCESS . " Deleted: $names");
    redirect('users.php');
    exit();
}

这里可以进行一些改进，包括效率（将许多小的单个查询合并为几个较大的查询）和错误处理（不要在第一个错误时重定向，而是在所有处理完成后重定向到一个包含成功和错误列表的页面），但这是基本思想。

这里有一个快速的改变，可以完成所有的操作，即使其中一个错误：

if ($_POST['doDelete'] == 'Delete') {
    $deleted = array();
    $errored = array();
    if (!empty($_POST['u'])) {
        foreach ($_POST['u'] as $uid) {
            $id = escape($uid);
            $username = get_user_name_from_id($uid);
            $delete = Nemesis::query("DELETE FROM users WHERE id = '{$id}' AND id <> '{$_SESSION[user_id]}'");
            if (!$delete) {
                $errored[] = $username;
            } else {
                $deleted[] = $username // push name to array after deletion is successful
            }
        }
    }
    /* The $deleted array now holds the names of the deleted users.
     * The $errored array now holds the names of users who were not deleted due to errors.
     * Do with them what you want.
     */
    $msg = new Messages();
    $names_deleted = implode(",", $deleted)
    $msg->add('s', QUERY_DELETE_SUCCESS . " Deleted: $names_deleted");
    if (count($errored) > 0) {
        $names_errored = implode(",", $errored)
        $msg->add('e', QUERY_ERROR . " Did not delete: $names_errored");
    }
    redirect('users.php');
    exit();
}

Answer 2

您可以在uid上循环时将名称添加到数组中，方法如下：

$names = array();
if (!empty($_POST['u'])) {
    foreach ($_POST['u'] as $uid) {
        $names[] = get_user_name_from_id($uid);
        $id = escape($uid);
        $delete = Nemesis::query("DELETE FROM users WHERE id = '{$id}' AND id <> '{$_SESSION[user_id]}'");
        if (!$delete) {
            $msg->add('e', QUERY_ERROR);
            redirect('users.php');
            exit();
        }
    }
}

然后，当您想要输出确认消息时，您可以将该数组转换为逗号分隔的字符串，其中包含以下内容：

$names = implode(', ',$names);
$message = "Deleted $names";