通过内部数组的字段之一对多维数组进行排序 [英] Sort a multidimensional array by one of the fields of the inner array

问题描述

如何按内部数组的字段之一对多维数组排序?

How do I sort a multidimensional array by one of the fields of the inner array?

在Java中，如何创建这样的多维数组?以及如何按X字段对其进行排序?有例子吗?

In Java, How I can create a multidimensional array like this? and how I can sort it by X field? Any examples?

Array
(
    [0] => Array
        (
            [name] => Sony TV
            [price] => 600.00
        )

    [1] => Array
        (
            [name] => LG TV
            [price] => 350.00
        )

    [2] => Array
        (
            [name] => Samsung TV
            [price] => 425.00
        )  
}

推荐答案

您拥有的东西根本看起来并不像多维数组(嗯，它看起来像PHP多维数组，而不是Java多维数组)，而是对象数组，其中每个对象都有一个名称"和一个价格"字段.

What you have doesn't look like a multidimensional array at all (well, it looks like a PHP multidimensional array, but not a Java one), but rather an array of objects, where each object has a "name" and a "price" field.

在这种情况下，您应该首先创建对象的类.我们称之为Product:

In these case you should first create your object's class. Let's call it Product:

public class Product implements Comparable<Product> {
    private String name;
    private BigDecimal price;

    public Product(final String name, final BigDecimal price) {
        this.name = name;
        this.price = price;
    }

    @Override
    public int compareTo(final Product other) {
        return name.compareTo(other.name);
    }

    /* Other methods. */

    /* Getters and setters for price and name. */

}

您会注意到该类实现了 ，并具有方法compareTo.这意味着可以订购产品的集合.然后，将Product放入数组中，并使用Arrays.sort()方法对其进行排序:

You'll notice that this class implements Comparable<Product> and has a method compareTo. This means that a collection of products can be ordered. Then, you put your Products into an array and you use the Arrays.sort() method to sort it:

Product[] products = new Product[3];
products[0] = new Product("Sony TV", new BigDecimal("600.00"));
products[1] = new Product("LG TV", new BigDecimal("350.00"));
products[2] = new Product("Samsung TV", new BigDecimal("425.00"));
Arrays.sort(products);

编辑:我错过了您想要按任何字段进行排序的事实.在这种情况下，您需要比较器.每个字段需要一个:

I missed the fact that you wanted to sort by any field. In this case, you need Comparators. You'll need one per field:

Comparator<Product> nameComparator = new Comparator<Product>() {
    @Override
    int compare(final Product p1, final Product p2) {
        return p1.getName().compareTo(p2.getName());
    };
Comparator<Product> priceComparator = new Comparator<Product>() {
    @Override
    int compare(final Product p1, final Product p2) {
        return p1.getPrice().compareTo(p2.getPrice());
    };

然后，只需将您的比较器提供给Array.sort()方法:

Then, just give your comparators to the Array.sort() method:

 Arrays.sort(products, nameComparator);
 /* or */
 Arrays.sort(products, priceComparator);

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