Question

I would expect identical output to be produced but instead I get the following

string1,string2
WrappedArray(string1, string2)

.

  def appendcsv(fileName: String, args: Any*) {
    val fw = new FileWriter(fileName, true)
    val line = args.mkString(",")
    fw.write(line + "\r\n")
    fw.close()
  }
  def printcsv(fileName: String, args: Any*) {
    appendcsv(fileName, args)
  }
  appendcsv("test.csv", "string1", "string2")
  printcsv("test.csv", "string1", "string2")

Answer 1

Because when you do appendcsv(fileName, args), you are passing a WrapedArray instead of multiple arguments as you will expected. So in facts appendcsv only received only one argument of WrappedArray, not two strings.

You could use appendcsv(fileName, args: _*) to expend array to multiple arguments, and it will be what you would expected.