You can have this in Scala. List("a", "b").map(_.toUpperCase).mkString(",") It's the shorthand for: List("a", "b").map(elem => elem.toUpperCase).mkString

You can have this in Scala. List("a", "b").map(_.toUpperCase).mkString(",") It's the shorthand for: List("a", "b").map(elem => elem.toUpperCase).mkString(",") (Which shows the firstly proposed feature :-))