add elements in scala lists

Question

I am still learning Scala and I am facing the following issue. Currently I have the following list in input

val listA=List("banana,africa,1,0",
"apple,europe,1,2",
"peas,africa,1,4")

The wanted output is :

val listB=list("banana,africa,1,0,1",
"apple,europe,1,2,3",
"peas,africa,1,4,5")

My aim is to add an element corresponding to the sum of the two last elements for each line in the list. I wrote the following basic function

 def addSum(listin:List[String]):List[String]= {
  listin.map(_.split(",")).map(d => d + "," + d(2)+d(3))

}

this is not working any suggestion aboit a better way to do it please

Thanks a lot

Answer 1

Simple solution is to do something like below

listA.map(str => str.split(",")).map(arr => (arr ++ Array(arr(2).toInt+arr(3).toInt)).mkString(","))