将 Option[Any] 转换为 int [英] Cast Option[Any] to int

问题描述

如何将其转换为 Int 而不是 Some(Int)

How do I cast this to an Int and not Some(Int)

val a: Option[Any] = Some(1)

我尝试了 toInt 并且它给出了一个错误 value toInt is not a member of Option[Any]

I tried toInt and it gave an error value toInt is not a member of Option[Any]

推荐答案

你可以做 a.get.asInstanceOf[Int] 但是它是不安全的.更好的方法是保留类型信息，即使用 Option[Int] 而不是 Option[Any].那么你就不需要用 asInstanceOf 来转换结果.

You could do a.get.asInstanceOf[Int] however it is unsafe. A better way would be to retain the type information i.e. using a Option[Int] instead of an Option[Any]. Then you would not need to cast the result with asInstanceOf.

val a:Option[Int] = Some(1)
val i = a.get

直接使用 get 是不安全的，因为如果 Option 是 None 会抛出异常.所以使用 getOrElse 更安全.或者您可以在 a 上使用模式匹配来获取值.

Using get directly is unsafe since if the Option is a None an exception is thrown. So using getOrElse is safer. Or you could use pattern matching on a to get the value.

val a:Option[Any] = Some(1) // Note using Any here
val i = (a match {
  case Some(x:Int) => x // this extracts the value in a as an Int
  case _ => Int.MinValue
})

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