Rewrite 'for' loop from Java to Scala

Question

I need to convert some Java code to Scala. I have such source. How to rewrite it in Scala? Question may be simple. But it match harder then for(i <- 1 until 10) {} examples in documentation.

for (int i = password.length(); i != 0; i >>>=1)
  { some code }

King regards, Alexey

Answer 1

If you want it to be as fast as possible--which I am assuming is the case given the shift operation--then you should use a while loop:

var i = password.length()
while (i != 0) {
  // some code
  i >>>= 1
}

It's one of the few cases where Java is more compact than Scala given the same operation.

You could also use tail recursion:

final def passwordStuff(password: Password)(i: Int = password.length): Whatever = {
  if (i != 0) {
    // Some code
    passwordStuff(password)(i >>> 1)
  }
}

which will compile into something of the same speed as the while loop (in almost every case, anyway).