object Main { def main(args: Array[String]) { val sites = Map("w3xue" -> "www.w3xue.com", "google" -> "www.google.com") println("show(sites.get( \"w3xue\")) : " + show(sites.get( "w3xue")) ) println("show(sites.get( \"baidu\")) : " + show(sites.get( "baidu")) ) } def show(x: Option[String]) = x match { case Some(s) => s case None => "?" } }