Question

This is probably a basic scala question but not able to figure out how:

How can this java loop be expressed using Scala for:

for (int i=1;i<100000;i=2*i)

I understand this is one possible way:

  def loopByTwiceBefore(from:Int, to:Int)(f:Int=>Unit):Unit = {
    if (from<to){
        f(from)
        loopByTwiceBefore(from*2, to)(f);
    }
  }  

But is there a more canonical way to do this in Scala.

Answer 1

You can use the iterate function from Iterator (or from other classes like Stream, List etc.):

Iterator.iterate(1)(_*2).takeWhile(_ < 100000) foreach {...}