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Scala iterate over two consecutive elements of a list

How would we iterate over two consecutive elements of a list and apply the difference function For instance I have this :

val list = List(List("Eat", "Drink", "Sleep", "work"), List("Eat", "Sleep", "Dance"))

I want to iterate over these two consecutive elements and calculate the difference

I've tried this but I do not know how to iterate over each two consecutive elements

list.map((a,b) => a.diff(b))

the output should be List("Drink", "work")

Solution

  • If I understand correctly you probably want to iterate over a sliding window.

    list.sliding(2).map{
  case List(a, b) => a.diff(b)
  case List(a) => a
}.toList

    Alternatively you might also want grouped(2) which partitions the list into groups instead.