What is the difference between the methods iterator and view?

Question

scala> (1 to 10).iterator.map{_ * 2}.toList
res1: List[Int] = List(2, 4, 6, 8, 10, 12, 14, 16, 18, 20)

scala> (1 to 10).view.map{_ * 2}.force
res2: Seq[Int] =         


        

Answer 1

This page talks about when to use views.

In summary, views are a powerful tool to reconcile concerns of efficiency with concerns of modularity. But in order not to be entangled in aspects of delayed evaluation, you should restrict views to two scenarios. Either you apply views in purely functional code where collection transformations do not have side effects. Or you apply them over mutable collections where all modifications are done explicitly. What's best avoided is a mixture of views and operations that create new collections while also having side effects.