检查数组中的不允许键？

What is the best way to check if an array contains unallowed keys ?

$array = array("Apple" => 33, "Orange" => 22, "Dogs" => 77,);

$allowed = array("Apple", "Orange");

Desired output is:

if (!something($array,$allowed)){echo 'Unallowed data';}

Thanks

Use array_diff_key

$array = array("Apple" => 33, "Orange" => 22, "Dogs" => 77,);
$allowed = array("Apple", "Orange");
$allowed = array_flip($allowed);

$res = array_diff_key($array, $allowed);

print_r($res);

echo $allowedTxt = empty($res) ? "Allowed keys only" : "Not allowed keys";

$res contains unallowed data.

Assumes not allowed key is "Dogs"

Use array_intersect_key()

var_dump(array_intersect_key($array, array_flip($allowed)));

You can use array_diff() to find keys that are not allowed:

$keys = array_keys($array);
$notAllowed = array_diff($keys, $allowed);
var_dump($notAllowed); // "Dogs"

Here is a function that does this:

function something($array, $keys) {
    return ! array_diff(array_keys($array), $keys);
}
// Usage...
if ( ! something($array, $allowed)) {
    echo 'Unallowed data';
}

If you can use an associative (map) array for your allowed values, then you can perform the search on the allowed keys in O(1). With your current data structure, searching the allowed map, will take O(n) time.

$array = array("Apple" => 33, "Orange" => 22, "Dogs" => 77,);

$allowed = array("Apple" => 0, "Orange" => 1);

$found_not_allowed = 0;

foreach($array as $key => $value)
    if(!isset($allowed[$key]))
        $found_not_allowed++;

if($found_not_allowed > 0) 
    echo "Keys were found that are not allowed.";