在Scala中键入与Array数组不匹配(Type mismatch with Array of Array in Scala)

在Scala中键入与Array数组不匹配(Type mismatch with Array of Array in Scala)

我正在尝试构建一个数组数组，以将其作为方法的参数。 内部数组的值是任何类型的数据（AnyVal），例如Int或Double。

该方法的签名如下：

def plot[T <: AnyVal](config:Map[String, String], data:Array[Array[T]]): Unit = {

这是代码：

val array1 = (1 to 10).toArray val array2 = ArrayBuffer[Int]() array1.foreach { i => array2 += (getSize(summary, i)) } val array3 = new Array[Int](summary.getSize()) val arrays = ArrayBuffer[Array[AnyVal]](array1, array2.toArray, array3) # <-- ERROR1 Gnuplotter.plot(smap, arrays.toArray) # <-- ERROR2

但是，我有两个错误：

什么可能是错的？

I'm trying to build an array of an array to give it as a argument to a method. The value of inner arrays are any kind of data (AnyVal) such as Int or Double.

The method's signature is as follows:

def plot[T <: AnyVal](config:Map[String, String], data:Array[Array[T]]): Unit = {

This is the code:

val array1 = (1 to 10).toArray val array2 = ArrayBuffer[Int]() array1.foreach { i => array2 += (getSize(summary, i)) } val array3 = new Array[Int](summary.getSize()) val arrays = ArrayBuffer[Array[AnyVal]](array1, array2.toArray, array3) # <-- ERROR1 Gnuplotter.plot(smap, arrays.toArray) # <-- ERROR2

However, I have two errors:

What might be wrong?

最满意答案

Array是一个可变数据结构，不是协变的（ 这就是为什么 ）

因此， Array[Int]不是Array[AnyVal]的子类型，因此您无法在需要Array[AnyVal]位置传递它。

List会为您做什么吗？

如果性能很重要并且你真的需要使用Array ，你可以简单地将所有内容都转换为Array[Any]并完成它。

或者，如果您只需要一个Array[Any]作为传递给plot函数的最终类型，您可以使用List执行所有操作，并在最后使用toArray[Any]进行转换。

Array, being a mutable data structure, is not covariant (here's why)

So Array[Int] is not a subtype of Array[AnyVal], hence you cannot pass it where an Array[AnyVal] is expected.

Would a List do for you purposes?

In case performance matters and you really need to use Array, you can simply cast everything to an Array[Any] and be done with it.

Alternatively, if you just need an Array[Any] as the final type to pass to the plot function, you can do everything with List, and convert it with toArray[Any] at the very end.