scala - Scala：如何检查 Array[T] 的类型

Question

我有一个Array[T]，如何检查它的类型？

我试过

def check[T](a: Array[T]) = {
  a match {
    case _: Array[Int] => // create type specified IntVector
    case _: Array[Float] => // create type specified FloatVector
  }
}

编译器引发错误

Scrutinee is incompatible with pattern type, found: Array[Int], required: Array[T]

---

我想这样做的原因是，假设我能够枚举所有类型，而目前只有 Int 和 Float

def check[T](a: Array[T]) = {
  val base: Base = baseVector
  val derived = a match {
    case _: Array[Int] => base.asInstanceOf[IntVector]      
    case _: Array[Float] => base.asInstanceOf[FloatVector]
  }
  derived.run()
}
abstract class Base
  def run()
class IntVector extends Base
  override def run()
class FloatVector extends Base
  override def run()

标签： scalagenericspattern-matching

Answer 1

这对我有用：

def check[T](a: Array[T]) = {
  a match {
    case x if x.isInstanceOf[Array[Int]] => println("int")
    case y if y.isInstanceOf[Array[Float]]  => println("float")
    case _ => println("some other type")
  }
}