Scala 不再支持List.make，报错"value make is not a member of object List"

Question

通过示例时 http://aperiodic.net/phil/scala/s-99/p15.scala

// P15 (**) Duplicate the elements of a list a given number of times.
//     Example:
//     scala> duplicateN(3, List('a, 'b, 'c, 'c, 'd))
//     res0: List[Symbol] = List('a, 'a, 'a, 'b, 'b, 'b, 'c, 'c, 'c, 'c, 'c, 'c, 'd, 'd, 'd)

object P15 {
  def duplicateN[A](n: Int, ls: List[A]): List[A] =
    ls flatMap { List.make(n, _) }
}

行

ls flatMap { List.make(n, _) }

产生编译器错误

"value make is not a member of object List"

还有其他方法可以重写吗？

Answer 1

make 在 2.8.0 中弃用并在 2.11.x 中删除。

您可以使用

ls flatMap { List.fill(n)(_) }

Scala 不再支持List.make，报错"value make is not a member of object List"

Scala no longer supports List.make, error "value make is not a member of object List"

scala