如何从键返回 PHP 数组值？
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How to return PHP array value from key?
提问by dmubu
I am trying to generate a user's country based on the city selection in a select menu. I have generated the select menu using an associative array. I want to print "$city is in $country" but I cannot access the $country properly. This is what I have:
我正在尝试根据选择菜单中的城市选择生成用户的国家/地区。我使用关联数组生成了选择菜单。我想打印“$city is in $country”，但我无法正确访问 $country。这就是我所拥有的：
<?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");
?>
Any ideas? Thank you.
有任何想法吗？谢谢你。
回答by Spyros
You are trying to access the local foreach variable $country out of the foreach loop. You have to do that inside the loop.
您正在尝试从 foreach 循环中访问本地 foreach 变量 $country。您必须在循环内执行此操作。
Or you could just get the country from the cities array like :
或者你可以从城市数组中获取国家，例如：
$cities[$city];
回答by DevelRoot
...
<?php
$city = $_POST["city"];
print ("$city is in ".$cities[$city]);
?>
