format number with spaces thouthands separator

Nowhere could I find it. I therefore implemented mine own method (using flatMap) and practicing some Scala. Here is mine try (scastie)

def format(n: Long): String = {

 (n.toString.reverse.grouped(3).flatMap(s => ' ' + s) mkString "").reverse.trim

} //> format: (n: Long)String

format(1) //> res0: String = 1

format(12) //> res1: String = 12

format(123) //> res2: String = 123

format(1234) //> res3: String = 1 234

format(123444444) //> res4: String = 123 444 444

You can also format numbers online