我从CodeIgniter中的控制器获得以下结果数组：
Array
(
[cities] => Array
(
[0] => stdClass Object
(
[id] => 1
[name] => Jersey City
[state] => stdClass Object
(
[id] => 1
[name] => New Jersey
)
)
[1] => stdClass Object
(
[id] => 2
[name] => Philadelphia
[state] => stdClass Object
(
[id] => 2
[name] => Pennsylvania
)
)
)
)
现在我想创建一个具有这些值的下拉框，以便该框具有城市、州。
Jersey, New Jersey
Philadelphia, Pennsylvania
这就是我试图实现这一目标的方式：
<?php
foreach($cities as $city) {
echo "<option value='$city->id'>$city->name, $city->state->name</option>";
}
?>
当我尝试访问时：
$city->state->name
我收到以下错误：
<p>Severity: 4096</p>
<p>Message: Object of class stdClass could not be converted to string</p>
如果有人能指导我从状态数组中获取名称的正确方法，我将不胜感激。
谢谢！
您正在使用一个对象，但是当您echo它时，PHP 会尝试将其转换为字符串并失败，从而生成上述错误消息。为了避免这种情况，您可以将变量包装在大括号{ }中，如下所示：
foreach($cities as $city) {
echo "<option value='{$city->id}'>{$city->name},
{$city->state->name}</option>";
}
或者，您也可以使用sprintf()（在我看来，这更干净一些）：
foreach($cities as $city) {
echo sprintf("<option value='%d'>%s, %s</option>",
$city->id, $city->name, $city->state->name);
}
试试这个：
foreach($cities as $city) {
foreach($city->state as $state) {
echo "<option value='$city->id'>$city->name, $state->name</option>";
}
}
或者试试这个：
foreach($cities as $city) {
echo "<option value='$city->id'>$city->name, $city->state[0]->name</option>";
}