值对的 Java 集合?(元组?) [英] A Java collection of value pairs? (tuples?)

问题描述

我喜欢 Java 的 Map，您可以在其中定义 Map 中每个条目的类型，例如 .

I like how Java has a Map where you can define the types of each entry in the map, for example <String, Integer>.

我正在寻找的是一种集合，其中集合中的每个元素都是一对值.该对中的每个值都可以有自己的类型(如上面的 String 和 Integer 示例)，这是在声明时定义的.

What I'm looking for is a type of collection where each element in the collection is a pair of values. Each value in the pair can have its own type (like the String and Integer example above), which is defined at declaration time.

集合将保持其给定的顺序，并且不会将其中一个值视为唯一键(如在地图中).

The collection will maintain its given order and will not treat one of the values as a unique key (as in a map).

本质上，我希望能够定义 类型或任何其他 2 种类型的 ARRAY.

Essentially I want to be able to define an ARRAY of type <String,Integer> or any other 2 types.

我意识到我可以创建一个只包含 2 个变量的类，但这似乎过于冗长.

I realize that I can make a class with nothing but the 2 variables in it, but that seems overly verbose.

我也意识到我可以使用 2D 数组，但由于我需要使用不同的类型，我必须将它们设为 OBJECT 数组，然后我必须一直进行转换.

I also realize that I could use a 2D array, but because of the different types I need to use, I'd have to make them arrays of OBJECT, and then I'd have to cast all the time.

我只需要在集合中存储对，所以每个条目只需要两个值.如果不走课堂路线，是否存在这样的事情?谢谢！

I only need to store pairs in the collection, so I only need two values per entry. Does something like this exist without going the class route? Thanks!

推荐答案

Pair 类是那些给我"泛型示例之一，很容易自己编写.例如，在我的头顶:

The Pair class is one of those "gimme" generics examples that is easy enough to write on your own. For example, off the top of my head:

public class Pair<L,R> {

  private final L left;
  private final R right;

  public Pair(L left, R right) {
    assert left != null;
    assert right != null;

    this.left = left;
    this.right = right;
  }

  public L getLeft() { return left; }
  public R getRight() { return right; }

  @Override
  public int hashCode() { return left.hashCode() ^ right.hashCode(); }

  @Override
  public boolean equals(Object o) {
    if (!(o instanceof Pair)) return false;
    Pair pairo = (Pair) o;
    return this.left.equals(pairo.getLeft()) &&
           this.right.equals(pairo.getRight());
  }

}

是的，它存在于网络上的多个位置，具有不同程度的完整性和功能.(我上面的例子是不可变的.)

And yes, this exists in multiple places on the Net, with varying degrees of completeness and feature. (My example above is intended to be immutable.)

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