如何合并多个输出并存储在单个变量中

如何将以下输出合并为单行并存储在单个变量中

我有以下输出

        THICKNESS: .1875ItemID: VSG-10
        THICKNESS: .1875ItemID: VSG-7
        THICKNESS: .1875ItemID: VSG-8
        THICKNESS: 10ItemID: VSG-22
        THICKNESS: 10ItemID: VSG-23
        THICKNESS: .1875ItemID: VSG-3
        THICKNESS: .1875ItemID: VSG-6
        THICKNESS: .1875ItemID: VSG-4
        THICKNESS: .1875ItemID: VSG-27

这是我用来获取上述输出的代码

        $d = explode(',', $row['ItemDesc']);
        $c = explode(',', $row['ItemIDgroup']);
           foreach($d as $k => $v)
            {
                 $d2 = explode(' ',$v); 
                 $output = "THICKNESS: " . $d2[1] ."ItemID: ". $c[$k];
                 echo $output;
                 echo"<br/>";
             }

我想结束并想存储在单个变量中

   THICKNESS: .1875ItemID: VSG-10, THICKNESS: .1875ItemID: VSG-7,THICKNESS: .1875ItemID: VSG-8, ....