重复的字符串，替换为scala

Question

我有一个包含以下行的CSV文件：

val s = "\"a,b,c,d\",2,3,4"    // it also could have been "a,b,d",2,3,4 or "a,,d",2,3,4 ...
val regex = new Regex(
    "\"([^,]+)(,+([^,]*))+\"",
    "begin",
    "test", "end")
val line = regex.replaceAllIn(s, m => m.group("begin") + "#" + m.group("end"))

结果是：     a＃d，2,3,4

但我想这样：a＃b＃c＃d，2,3,4

有没有办法获得正则表达式检测到的所有值？