php - 如何从键返回 PHP 数组值？

Question

我正在尝试根据选择菜单中的城市选择生成用户所在的国家/地区。我使用关联数组生成了选择菜单。我想打印“$city is in $country”，但我无法正确访问 $country。这是我的:

<?php
$cities = array("Tokyo" => "Japan", "Mexico City" => "Mexico", 
"New York City" => "USA", "Mumbai" => "India", "Seoul" => "Korea",
"Shanghai" => "China", "Lagos" => "Nigeria", "Buenos Aires" => "Argentina", 
"Cairo" => "Egypt", "London" => "England");
?>

<form method="post" action="5.php">
<?php
echo '<select name="city">';

foreach ($cities as $city => $country)
{
echo '<option value="' . $city . '">' . $city . '</option>';
}

echo '<select>';

?>

<input type="submit" name="submit" value="go" />
</form>
<?php
$city = $_POST["city"];

print ("$city is in $country");
?>

有什么想法吗？谢谢。

Answer 1

您正试图在 foreach 循环之外访问本地 foreach 变量 $country。您必须在循环内执行此操作。

或者您可以从城市数组中获取国家/地区，例如:

$cities[$city];