php array_search查找索引值

I have 2 arrays $userArray and $differentArray.

question: I am trying to find the index value from $userArray where $userId matches from $differentArray so that i can pull the first/last names

print_r of $userArray outputs this:

    Array
    (
        [0] => Array
            (
                [userId] => ID Object
                    (
                        [_unknown:protected] => 
                        [id_:protected] => 8k6Y4FTrnxKY45XrVkXvVJhL
                    )
                [firstName] => Joe
                [lastName] => Smith
            )

        [2] => Array
            (
                [userId] => ID Object
                    (
                        [_unknown:protected] => 
                        [id_:protected] => pCvR9qvIgGv8WyejcKmRtGD8
                    )
                [firstName] => Sue
                [lastName] => Miller
            )

    )

print_r of $differentArray outputs this:

        Array
    (
            [0] => Array
                    (
                            [date] => 1363800434868
                            [userId] => ID Object
                                    (
                                            [_unknown:protected] => 
                                            [id_:protected] => 8k6Y4FTrnxKY45XrVkXvVJhL
                                    )

                            [someTxt] => aaaa
                    )

            [1] => Array
                    (
                            [date] => 1363800858828
                            [userId] => ID Object
                                    (
                                            [_unknown:protected] => 
                                            [id_:protected] => 8k6Y4FTrnxKY45XrVkXvVJhL
                                    )

                            [someTxt] => cccc
                    )

            [2] => Array
                    (
                            [date] => 1363817564430
                            [userId] => ID Object
                                    (
                                            [_unknown:protected] => 
                                            [id_:protected] => pCvR9qvIgGv8WyejcKmRtGD8
                                    )

                            [someTxt] => ccc
                    )
    )

and here is my attempt, but it only outputs Joe Smith
* $differentArray is constructed the same way as $userArray

    $i = 0;
    while ($i < count($differentArray)){
        $userId = $differentArray[$i]['userId'];
        $key = array_search( $userId, $userArray );
        $firstName = $userArray[$key]['firstName'];
        $lastName = $userArray[$key]['lastName'];
         $i++;
    }

thank you.

Man, use foreach.

$i = 0;
while ($i < $total) {
    $userId = $differentArray[$i]['userId'];
    // $key = array_search($userId, $userArray);
    foreach ($userArray as $k => $user) {
        if($user["userId"] == $userId){
            $key = $k;
            break; // avoid useless loop
        }
    }
    $firstName = $userArray[$key]['firstName'];
    $lastName = $userArray[$key]['lastName'];
    $i++;
}

I'm not sure what that ID object is, but I assume it has a __toString method that returns the id property.

$output = array();
foreach ($differentArray as $user) {
    foreach ($userArray as $searchedUser) {
        if ($searchedUser['userId'] == $user['userId']) {
            $output[] = $searchedUser;
        }
    }
}

That will put the users you're looking for in $output array. This way you won't need the indices no more. You can just iterate over $output to pull out the values to variables. Eg.

foreach ($output as $user) {
    list($userId, $firstName, $lastName) = $user;
    // do your code here
}

If you're certain that there can only be one match in $userArray than you can break out from the loop when you find it or pull out the first one from the $output array.

I did a lot of guessing posting that answer since you didn't provide the $differentArray structure nor specified what it is you're actually expecting.