วนลูป for โดยมี ตัวแปร 2 ตัวติดกัน แล้ว error :: Parse error: syntax error, unexpected T_VARIABLE

<?php
    if(isset($_POST["submit_send_session"]))
    {
        for ( $j=0;$j<count($_POST["addons_select_main"]);$j++ )
        {
            $k = $j+1;

            $_SESSION["addons_select_sub_count$k"] = count($_POST["addons_select_sub$k"]);
                for($i=0;$i<count($_POST["addons_select_sub$k"]);$i++)
                    {
                        $addons_select_sub$k = $_POST['addons_select_sub$k'][$i];
                        $addons_select_price_sub$k = $_POST['addons_select_price_sub$k'][$i];
                        $addons_select_article_sub$k = $_POST['addons_select_article_sub$k'][$i];
                        $addons_select_type_sub$k = $_POST['addons_select_type_sub$k'][$i];

                            if ($addons_select_sub$k != '')
                                {
                                    $_SESSION["addons_select_sub$k$i"] = $addons_select_sub$k;
                                    $_SESSION["addons_select_price_sub$k$i"] = $addons_select_price_sub$k;
                                    $_SESSION["addons_select_article_sub$k$i"] = $addons_select_article_sub$k;
                                    $_SESSION["addons_select_type_sub$k$i"] = $addons_select_type_sub$k;
                                }
                    }
        }
    }
session_write_close();
?>