Apply function on each elements in one list using element from others list as argument?

Question

I am not sure how to call this but I want something like this.

val x = List(1,2,3,...)
val y = List(4,5,6,...)
//want a result of List(1+4, 5+6, 7+8,...)

Is there an easy way to do this in scala ? My current implementation involving using looping from 0 to x.lenght which is pretty ugly. And if it is possible, I would like the solution that could use over nth number of list and maybe with other type of operator beside +.

Thanks !

Answer 1

In response to "what if I have more than 3 list?":

def combineAll[T](xss: Seq[T]*)(f: (T, T) => T) = 
  xss reduceLeft ((_,_).zipped map f)

Use like this:

scala> combineAll(List(1,2,3), List(2,2,2), List(4,5,6), List(10,10,10))(_+_)
res5: Seq[Int] = List(17, 19, 21)

edit: alternatively

def combineAll[T](xss: Seq[T]*)(f: (T, T) => T) = 
  xss.transpose map (_ reduceLeft f)

does the same and is probably more efficient.