比较2个PHP数组并过滤掉结果

Question

I've been struggling for a while now. I have 2 arrays that I want to compare with each other. A user array and a lesson array. The Keys in the lesson array are the ID's of that lesson

Lesson Array:

Array(
    // The key in this array ([143] or [13]) is the lesson ID each lesson contains one ore more topics
    [143] => Array (
        [0] => 315 // example: 315 is a topic ID within lesson 143
        [1] => 311
        [2] => 176
        [3] => 145
    )

    [13] => Array (
        [0] => 27
        [1] => 25
    )
)

The user array contains only the information about which topics that user has completed. Topic with lesson ID's that are not completed don't exist in this array.

Main question: I want to compare the topic ID's of the user array to the Lesson array. And I want to put the topics that aren't completed in a seperate array.

User array

Array (
    [0] => Array (
        [143] => Array (
            [145] => 1 // (this 1 means it is completed, this key is a topic ID)
            [176] => 1
        )
    )

    [1] => Array (
        [13] => Array (
            [25] => 1
        )
    )

)

In this example above the result i want to get is an array with non matching id's like:

$result = array( 143 => array(311,315), 13 => array(27))

I hope it's a little bit clear.

If anyone can point me out in the right direction I'll be very glad! I tried a lot of things but to post them all here it's not clarifying the main question.

Answer 1

you have to use array_keys and array_diff. Online compile at My answer

Arrays

$lesson = array(
    "143" => array("315", "311", "176", "145"),
    "13" => array("27", "25")
);

$user = array(
    array("143" => array("145" => "1", "176" => "1")),
    array("13" => array("25" => "1"))
);

Mechanism/ process

$result = array();
foreach ($user as $key => $value) {
    foreach ($value as $key2 => $value2) {
        $result[$key2] = array_diff($lesson[$key2], array_keys($value2));
    }
}

Result

echo '<pre>';
print_r($result);
echo '</pre>';

Output

Array
    (
        [143] => Array
        (
            [0] => 315
            [1] => 311
        )
        [13] => Array
        (
            [0] => 27
        )
)