Array
(
    [0] => Array
        (
            [id] => 7869296252
            [email] => nidhi@gmail.com
            [assigned_to] =>         )

    [1] => Array
        (
            [id] => 9981114545
            [email] => test@gmail.com
             [assigned_to] =>
        )

    [2] => Array
        (
            [id] => 5444546546
             [email] => test1@gmail.com
             [assigned_to] =>
        )

    [3] => Array
        (
            [id] => 35454545
             [email] => test2@gmail.com
             [assigned_to] =>
        )

    [4] => Array
        (
            [id] => 45345345
             [email] => test3@gmail.com
              [assigned_to] =>
        )

    [5] => Array
        (
            [id] => 3453454
            [email] => tesrgt@gmail.com
            [assigned_to] =>
        )

    [6] => Array
        (
            [id] => 45345345
            [email] => test@gmail.com
            [assigned_to] =>
        )

Array
(
    [0] => 45
    [1] => 542
    [2] => 543
)
I want to array like:
Array
(
    [45] => Array
        (
            [0] => Array
                (
                    [id] => 9981114545
                    [email] => nidhi@gmail.com
                    [assigned_to] =>
                )

            [1] => Array
                (
                    [id] => 45345345
                    [email] => test@gmail.com
                    [assigned_to] =>
                )
     [2] => Array
                (
                    [id] => 9981114545
                    [email] => test@gmail.com
                    [assigned_to] =>
                )


        )

    [542] => Array
        (
            [0] => Array
                (
                    [id] => 5444546546
                    [email] =>
                    [assigned_to] =>
                )

            [1] => Array
                (
                    [id] => 3453454
                    [email] =>
                    [assigned_to] =>
                )
    [2] => Array
                (
                    [id] => 9981114545
                    [email] => test@gmail.com
                    [assigned_to] =>
                )


        )
[543] => Array
        (
            [0] => Array
                (
                    [id] => 35454545
                    [email] =>
                    [assigned_to] =>
                )

            [1] => Array
                (
                    [id] => 35454545
                    [email] =>
                    [assigned_to] =>
                )
    [2] => Array
                (
                    [id] => 9981114545
                    [email] => test@gmail.com
                    [assigned_to] =>
                )


        )

)

for($i = 0; $i < $no_of_users; $i++) {
    for ($c = 0; $c < $allot; $c++) {
        if(!array_key_exists($users[$i], $final_csv_data)){
             $alloted_cids[$users[$i]] = array();
             $alloted_cids[$users[$i]] = $final_csv_data[$i];
                 array_pop($final_csv_data[$i]);
        }else {
            $alloted_cids[$users[$i]] = $final_csv_data[$i];
            array_pop($final_csv_data[$i]);
        }
    }
    if($remain > 0){
        for($x = 0; $x<$remain; $x++){
            $alloted_cids[$users[$x]] = $final_csv_data[$i];
            array_pop($final_csv_data[$i]);
        }
    }
}