不同类型的数组 [英] Arrays of different types

问题描述

是否可以拥有包含两种不同类型数据的数组？我想要一个包含double和字符串的数组。我尝试过：

Is it possible to have an array that contains two different types of data? I want to have an array that contains a double and also a string. I attempted:

ArrayList<double><String> array;

但这不起作用。

对不起这个愚蠢的问题，但已经有一段时间了，因为我使用过这样的东西..你能否刷新我的记忆，我将如何声明和填充这样的数组？

Sorry for the silly question, but it has been a while since I have used something like this.. Can you refresh my memory on how would I declare and populate such an array?

然后再向前迈进一步，如果可能，我想用双排序数组？

And then to take it a step further, I would like to sort the array by the double if possible?

谢谢！

推荐答案

首先，值得清楚的是数组与 ArrayList 之间的区别 - 它们不是完全相同的事情。

Firstly, it's worth being clear about the difference between an array and an ArrayList - they're not the same thing at all.

然而，在任何一种情况下，你都无法做你想做的事。你可能来的最接近的是声明你自己的类型。 （编辑：我原来的代码有一个双或一个字符串...我现在把它改成了一个双和一个字符串。让我知道这个改变是否不是你的想法。）

However, in either case you can't do what you want. The closest you can probably come is declaring your own type. ( My original code had a double or a string... I've now changed it to be a double and a string. Let me know if this change isn't what you had in mind.)

public final class DoubleAndString
{
    private final String stringValue;
    private final double doubleValue;

    public DoubleAndString(String stringValue, double doubleValue)
    {
        this.stringValue = stringValue;
        this.doubleValue = doubleValue;
    }

    public String getString()
    {
        return stringValue;
    }

    public String getDouble()
    {
        return doubleValue;
    }
}

然后创建 ArrayList< DoubleAndString> 或 DoubleAndString [] 。

现在，这感觉有点香草味当下 - 大概是双重和字符串值实际上有更大的含义 - 例如名称和分数。如果是这样，请将其封装在更恰当描述配对的类型中。

Now, this feels somewhat vanilla at the moment - presumably the double and string values actually have a greater meaning - a name and a score, for example. If so, encapsulate that in a type which describes the pairing more appropriately.

至于订购 - 你可以制作 DoubleAndString 实现 Comparable< DoubleAndString> - 但除非那是唯一的自然顺序，这是有道理的，我会写一个 Comparator< DoubleAndString> ：

As for ordering - you could make DoubleAndString implement Comparable<DoubleAndString> - but unless that's the only natural ordering which makes sense, I'd write a Comparator<DoubleAndString>:

public class DoubleComparator implements Comparator<DoubleAndString>
{
    public int compare(DoubleAndString ds1, DoubleAndString ds2)
    {
        return Double.compare(ds1.getDouble(), ds2.getDouble());
    }
}

然后你可以使用收藏.sort 对 ArrayList< DoubleAndString> 或 Arrays.sort 进行排序以对数组进行排序。

Then you can use Collections.sort to sort an ArrayList<DoubleAndString> or Arrays.sort to sort an array.

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