Scala function programming

1. Arbitrary multi parameters funcs

sum(1,2,3,4,5) = sum(1 to 5: _*)
the equal '=' can be ignored if there is none  return val

def sum(args: Int*) = {
    var result = 0
    for(arg <- args) result += arg
    result    
}

 

　　scala Array Buffer to Java List:

import scala.collection.JavaConversions.bufferAsJavaList
import scala.collection.mutable.ArrayBuffer
val command = ArrayBuffer("ls","-al","/home/mike")
val pb = new ProcessBuilder(command)

　　reverse operation

import scala.collection.JavaConversion.asScalaBuffer
import scala.collection.mutable.Buffer
val cmd:Buffer[String] = pb.command()

　　Hash Map

val hs01 = Map("s01" -> 342342,"s02" -> 4245)
hs01.getOrElse("s01",0)