Question

I’m programming a PHP quiz application and am having some trouble with the scoring mechanism. Specifically, I have 2 arrays that I’m comparing to determine if an answer is correct or not.

I want to verify that all values of one array are found in another array. For example, if the correct answer

Array
(
    [0] => Proprietary user community
    [1] => Surveys
    [2] => Voice
    [3] => Online chat
    [4] => Web
    [5] => Email
    [6] => Social media
)

And the user provided answer is:

Array
(
    [0] => Surveys
    [4] => Online chat
    [6] => Email
) 

The system return incorrect, because all correct values have not been provided. Similarly, if the user provided answer looks like this:

Array
(
    [0] => Proprietary user community
    [1] => Surveys
    [2] => Voice
    [3] => Online chat
    [4] => Web
    [5] => Email
    [6] => Social media
    [7] => Phone
    [8] => Live chat
)

The the answer would be correct, if though additional answers have been provided.

Any ideas? I’ve been thinking of using array_intersect() but there has to be a more elegant solution.

Any help is much appreciated!

Answer 1

Just intersect the arrays and compare sizes.

$answer_key = array(/* your answer key here */);
$user_answers = array(/* user answers here */);

$intersection = array_intersect($answer_key, $user_answers);

if (count($answer_key) === count($intersection)) {
    // winner, winner, chicken dinner
} else {
    // fail
}