Question

以下是代码：

<?php

//Starting session

session_start();

//Includes mass includes containing all the files needed to execute the full script
//Also shows homepage elements without customs

require_once ('includes/mass.php');

$username = $_SESSION['username'];

if (isset($username))

{   

//Query database for the users networths

$sq_l = "SELECT * FROM user ORDER BY worth";

$sql_query_worth = mysql_query($sq_l);

while ($row = mysql_fetch_assoc($sql_query_worth))

      {

         $dbusername = $row['username'];

         $dbworth    = $row['worth'];

            foreach ($dbusername as $dbuser)

                {
                    echo ". USER: ".$dbuser." Has a networth of:  ".$dbworth;

                }
      }               
}

?>

有三个结果。这是错误。

这是错误消息：

警告：第32行的C：\ xampp \ htdocs \ Mogul \ richlist.php中为foreach（）提供的参数无效

Answer 1

只需改变：

        foreach ($dbusername as $dbuser)

            {
                echo ". USER: ".$dbuser." Has a networth of:  ".$dbworth;

            }

到：

echo ". USER: ".$dbusername." Has a networth of:  ".$dbworth;

Answer 2

那是因为你没有将数组传递给foreach循环。试试这个：

while ($row = mysql_fetch_assoc($sql_query_worth))
{
    $dbusername = $row['username'];
    $dbworth    = $row['worth'];
    echo "USER: ".$dbusername ." Has a networth of:  ".$dbworth;              
}

Answer 3

foreach()遍历数组。最有可能$dbusername是一个字符串，这意味着您应该删除foreach()并直接回复$dbusername。

Answer 4

您正在尝试迭代像数组一样的字符串 - foreach需要array（）输入

Answer 5

不需要foreach循环;这应该会更好：

while ($row = mysql_fetch_assoc($sql_query_worth))
{
  $dbusername = $row['username'];
  $dbworth    = $row['worth'];
  // The username is in $dbusername
  // And the worth is in $dbworth
  // So, just use those :
  echo ". USER: ".$dbusername." Has a networth of:  ".$dbworth;     
}

基本上：

mysql_fetch_assoc将当前行的数据提取到$row
表示$row是一个数组，其中包含username和worth键
您要将这两个数组条目的值分配给$dbusername和$dbworth
- 现在包含字符串
- 并且可以直接使用：它们不包含任何子数组。

如果您希望更好地了解变量包含的内容，可以使用print_r或var_dump;例如，像这样：

while ($row = mysql_fetch_assoc($sql_query_worth))
{
  var_dump($row;)
  $dbusername = $row['username'];
  $dbworth    = $row['worth'];
  var_dump($dbusername, $dbworth);
  echo ". USER: ".$dbusername." Has a networth of:  ".$dbworth;     
}

Answer 6

为什么你需要那里的foreach？那不是阵列。你应该把它放在foreach之外。

echo ". USER: ".$dbuser." Has a networth of: ".$dbworth;

Answer 7

您正在正确呼叫foreach。它期望一个数组作为第一个参数。在这种情况下，只需删除foreach，因为您已经有一个while循环迭代数据库查询结果。

在我的foreach循环中出错

7 个答案: