A parameter of a function (normally the last one) may be marked with vararg modifier:

fun 
     
       asList(vararg ts: T): List
      
        {        val result = ArrayList
       
        ()        for (t in ts) // ts is an Array            result.add(t)        return result    }
       
      
     

allowing a variable number of arguments to be passed to the function:

val list = asList(1, 2, 3)

Inside a function a vararg-parameter of type T is visible as an array of T, i.e. the ts variable in the example above has type Array<out T>.

Only one parameter may be marked as vararg. If a vararg parameter is not the last one in the list, values for the following parameters can be passed using the named argument syntax, or, if the parameter has a function type, by passing a lambda outside parentheses.

When we call a vararg-function, we can pass arguments one-by-one, e.g. asList(1, 2, 3), or, if we already have an array and want to pass its contents to the function, we use the spread operator (prefix the array with *):

val a = arrayOf(1, 2, 3)val list = asList(-1, 0, *a, 4)

 1.一般是函数中的最后一个参数

2.在一个函数中只可以声明一个参数为vararg

3.如果可变参数不是函数中的最后一个参数，则后面的参数通过命名参数语法来传递参数值

4.如果参数类型是函数, 可以在括号之外传递一个

5.传递一个已有的数组则通过*号

@Test fun testPair() {        val list = listOf("hello", true, "world")        val array = list.toTypedArray()        printVararg(*array, lastPrams = "...list...")    }    fun printVararg(vararg params: Any, lastPrams: String) {        for (param in params) {            println("param : $param, lastPrams: $lastPrams")        }    }