CODEWITHSUNDEEP
phparrays
Jake
Jake

Reputation: 26107

Compare two arrays and list items that don't match on a key

I have the following two arrays:

userStatus
---------------
Array
(
    [0] => Array
        (      
            [Username] => [email protected]
            [Status] => Active
        )

    [1] => Array
        (           
            [Username] => [email protected]
            [Status] => Terminated
        )

    [2] => Array
        (           
            [Username] => [email protected]
            [Status] => OnVacation
        )
)

users
------
Array
(
    [0] => [email protected]
    [1] => [email protected]
    [2] => [email protected]
)

I want to write a snippet that brings up an array of all userStatus entries that do not match on Username field in the users Array.

How can I do this? I don't seem to find an efficient and fast way to do this in PHP.

Thanks

Upvotes: 1

Views: 230

Answers (3)

cmbuckley
cmbuckley

Reputation: 42458

This answer was originally me being facetious, and I would suggest that safarov's answer is the clearest, but here's a solution with a custom callback to array_diff:

$userStatus = array(
    array('Username' => '[email protected]', 'Status' => 'Active'),
    array('Username' => '[email protected]',    'Status' => 'Terminated'),
    array('Username' => '[email protected]',   'Status' => 'OnVacation'),
);

$users = array(
    '[email protected]',
);

var_dump(array_udiff($userStatus, $users, function($status, $user) {
    return $status['Username'] !== $user;
}));

Upvotes: 0

Billy
Billy

Reputation: 1253

With your current arrays there is no logical way to avoid traversing $users for every $userStatus which would use exponential time O(n^2) and could get out of hand.

If instead you could convert $users to a hash (perhaps array_flip) then you could do it in linear time O(n).

$usersHash = array_flip($users);

foreach ($userStatuses as $status) {
    if (!array_key_exists($status['username'], $usersHash)) {
        // do something with the user
    }
}

Check out this related post for some information regarding time complexity of common PHP functions.

Upvotes: 0

safarov
safarov

Reputation: 7804

$result = array();
foreach($userStatus as $value) {
     if(!in_array($value['Username'], $users) {
        $result[] = $value;
     }
}

print_r($result);

Upvotes: 2

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