Scala 中的元组和列表[Any] 之间的区别? [英] Difference between Tuple and List[Any] in Scala?

问题描述

目前，我正在学习 Scala 并阅读这本书在 Scala 中编程，其中说:与数组或列表不同，元组可以包含不同类型的对象."例如，以下元组包含 Int、String 和 Float.

Currently, I am learning Scala and reading this book Programming in Scala and which says, " Unlike an array or list, a tuple can hold objects with different types." For example, the following tuple contain Int, String and Float.

val tup = (1, "hello", 4.4)

再一次，这本书说，如果你想在列表/数组中有任何类型的元素，那么你可以使用任何数据类型."

Again, the book say, "If you want to have any type of element in list/array, then you can use Any Datatype."

val list = List[Any](1, "hello", 4.4)

那么，上面这两种方法有什么区别呢?一个比另一个有什么好处?

So, what is the difference between above these 2 approaches? what are the benefit of one over another?

推荐答案

Any 是 data-type ，就像 Int 或 String，但与它们不同.
Tuple 是一个容器，它可以容纳多种数据类型，即它可以包含不同数据类型的val，但是Tuple 将取决于 Tuple 中有多少元素，例如:

Any is a data-type , just like Int or String, but different from them.
Tuple is a container, which can hold multiple data-types, i.e. it can contain vals of different data-types, but the type of the Tuple will depend upon how many elements are there in the Tuple, so for example:

val tup = (1, "hello", 4.4) // type of tup here is scala.Tuple3 (Int, String, Double)
val tup = (2.3, null) // type of tup here is scala.Tuple2  (Double, Null)
val tup = (5:Any, "hello", 2.2) // type of tup here is scala.Tuple3 (Any, String, Double)

但是 Tuple 中每个元素的类型将被保持.另一方面，Any 就像一个原生数据类型，其中元素没有唯一的类型标识，无论是 String 还是 Int 或 Null 类型最初，将转换为单个数据类型 Any 并且将丢失所有类型信息.

But the type of each of the elements in the Tuple will be maintained. Any on the other hand, is like a homegenous data-type in which there's no unique type identity of the elements, be it a String or Int or Null type initially, will be converted to a single data-type Any and will lose all type-information.

更新:
Tuple 和 List[Any] 的区别在于，Tuple 可以容纳多种数据类型的元素，同时仍然保持单个元素.
虽然 List 或 Array 只能保存 单一 数据类型的元素，所以 List[Any] 将由 Any 类型的所有元素组成，因此它基本上会将所有元素(无论它们之前的数据类型如何)转换为 Any.

Update:
The difference between a Tuple and a List[Any] is that a Tuple can hold elements of multiple data types, still maintaining the data type of the individual elements.
While a List or Array can only hold elements of a single data type, so a List[Any] will consist of all elements of type Any , so it'll basically convert all the elements (irrespective of their earlier data-type) to Any.

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