如何使用两个数字作为地图键 [英] How to use two numbers as a Map key

问题描述

我有两个数字，我想将它们一起用作 Map 中的键。目前，我连接他们的字符串表示。例如，假设键编号是4和12.我使用：

I have two numbers and I want to use them together as a key in a Map. Currently, I'm concatenating their string representations. For example, suppose the key numbers are 4 and 12. I use:

String key = 4 + "," + 12;

地图被声明为 Map< String，Object> 。

我认为这太糟了！我喜欢使用 String 之外的其他键作为键！我想要最快的方式来创建这些键。

I think this is so bad! I like to use something other than a String as the key! I want the fastest way to create these keys.

谁有好主意？

推荐答案

创建一个包含两个数字并将其用作键的对象。例如：

Create an object that holds the two numbers and use it as the key. For example:

class Coordinates {

  private int x;
  private int y;

  public Coordinates(int x, int y) {
     ...
  }

  // getters

  // equals and hashcode using x and y
}

Map<Coordinates, Location> locations = new HashMap<Coordinates, Location>();

如果您喜欢使用数学方法，请参阅 This StackOverflow answer 。

If you prefer a mathematical approach, see this StackOverflow answer.

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