Is there a Scala equivalent of the Python list unpack (a.k.a. “*”) operator?

Question

In Python, we have the star (or \"*\" or \"unpack\") operator, that allows us to unpack a list for convenient use in passing positional arguments. For example:

Answer 1

There is no direct equivalent in scala. The closest thing you will find is the usage of _*, which works on vararg methods only. By example, here is an example of a vararg method:

def hello( names: String*) {
  println( "Hello " + names.mkString(" and " ) )
}

which can be used with any number of arguments:

scala> hello()
Hello
scala> hello("elwood")
Hello elwood
scala> hello("elwood", "jake")
Hello elwood and jake

Now, if you have a list of strings and want to pass them to this method, the way to unpack it is through _*:

scala> val names = List("john", "paul", "george", "ringo")
names: List[String] = List(john, paul, george, ringo)
scala> hello( names: _* )
Hello john and paul and george and ringo