Scala集合

var list = List(1,2,3,4)
println(list)

var foo = List()
println(foo)
var bar = Nil
println(bar)

var foo = "a" ::("b"::("c"::Nil))

println(foo.head)
var bar = Nil
println(bar.isEmpty)

var s = Set(1,3,3,7)
println(s)

var map = Map("one"->1,"two"->2,"three"->3)
println(map)

var x:Option[Int] =Some(1)
println(x)