Scala 中的显式类型转换 [英] Explicit Type Conversion in Scala

问题描述

假设我有以下代码:

abstract class Animal
case class Dog(name:String) extends Animal
var foo:Animal = Dog("rover")
var bar:Dog = foo //ERROR!

如何修复这段代码的最后一行?基本上，我只想做些什么，用类似 C 的语言就可以做到:

How do I fix the last line of this code? Basically, I just want to do what, in a C-like language would be done:

var bar:Dog = (Dog) foo

推荐答案

这是我自己想出来的.有两种解决方案:

I figured this out myself. There are two solutions:

1) 进行显式转换:

var bar:Dog = foo.asInstanceOf[Dog]

2) 使用模式匹配为您进行转换，这也会捕获错误:

2) Use pattern matching to cast it for you, this also catches errors:

var bar:Dog = foo match {
  case x:Dog => x
  case _ => {
    // Error handling code here
  }
}

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