Php Codeigniter-访问多维stdObject数组时出错

我从CodeIgniter中的控制器处获得以下结果数组：

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
            )
        )
    )
)

现在我想用这些值创建一个下拉框，这样框中就有城市、州

Jersey, New Jersey
Philadelphia, Pennsylvania

这就是我努力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>";
    }
?>

我发现以下错误：

<p>Severity: 4096</p>
<p>Message: Object of class stdClass could not be converted to string</p>

严重性：4096

消息：类stdClass的对象无法转换为字符串

如果有人能指导我如何从状态数组中获取名称，我将不胜感激

谢谢

试试这个：

foreach($cities as $city) {
    foreach($city->state as $state) {
        echo "<option value='$city->id'>$city->name, $state->name</option>";
    }
}

foreach($cities as $city) {
        echo "<option value='$city->id'>$city->name, $city->state[0]->name</option>";
    }

foreach（$cities作为$city）{
foreach（$city->state作为$state）{
回显“$city->name，$state->name”；
}
}

或者试试这个：

foreach($cities as $city) {
        echo "<option value='$city->id'>$city->name, $city->state[0]->name</option>";
    }

foreach（$cities作为$city）{
回显“$city->name，$city->state[0]->name”；
}

您正在处理一个对象，但是当您

echo

它时，PHP试图将其转换为字符串，但失败了，从而生成了上述错误消息。为了避免这种情况，可以将变量用大括号括起来，如下所示：

foreach($cities as $city) { 
    echo "<option value='{$city->id}'>{$city->name}, 
    {$city->state->name}</option>"; 
} 

---

非常感谢你的回答@用户2550387：很高兴我能帮忙：）

foreach($cities as $city) { 
    echo sprintf("<option value='%d'>%s, %s</option>", 
    $city->id, $city->name, $city->state->name); 
}