md = md.split(",").filter(_ != ddd).toList.mkString(",")
scala> val a:String = "a,d,e,f,g"
a: String = a,d,e,f,g
scala> a.split(",").filter(_ == "")
res1: Array[String] = Array()
scala> a.split(",").filterNot(_ != "")
res3: Array[String] = Array()
scala> a.split(",").filter(_!= "e").toList.mkString(",")
res4: String = a,d,f,g
scala> a.split(",").filter(_!= "").toList.mkString(",")
res5: String = a,d,e,f,g
scala> val b:String = ",,,,"
b: String = ,,,,
scala> b.split(",").filter(_!= "").toList.mkString(",")
res6: String = ""
scala> a.split(",").filter(_!= "").toList.mkString(",")
res7: String = a,d,e,f,g
scala> a.split(",").filter(_!= "e").toList.mkString(",")
res9: String = a,d,f,g
scala>
scala> val c:String = "e"
c: String = e
scala> a.split(",").filter(_!= c).toList.mkString(",")
res10: String = a,d,f,g
scala> a
res11: String = a,d,e,f,g
scala> val d:String = "tt"
d: String = tt
scala> a.split(",").filter(_!= d).toList.mkString(",")
res12: String = a,d,e,f,g
scala>