排序数组列表[重复]

Question

List<String> words = new ArrayList<>();  
words.add("9 hello");
words.add("98 food");
words.add("105 cat");
words.add("2514 human");
words.add("3 pencil");
words.sort(Comparator.reverseOrder());

"2514 human"
"105 cat"
"98 food"
"9 hello"
"3 pencil"

"98 food"
"9 hello"
"3 pencil"
"2514 human"
"105 cat"

Answer 1

我认为您应该创建一个类来表示列表中的元素。例如：

public class WordCount {
    public static final Comparator<WordCount> BY_COUNT;

    private static final Pattern PATTERN
            = Pattern.compile("\\s*([0-9]+)\\s+(.*)");

    public final int count;
    public final String word;

    public static WordCount parse(String s) {
        Matcher matcher = PATTERN.matcher(s);
        if (!matcher.matches()) {
            throw new IllegalArgumentException("Syntax error: " + s);
        }
        return new WordCount(
                Integer.parseInt(matcher.group(1)), matcher.group(2));
    }

    public WordCount(int count, String word) {
        this.count = count;
        this.word = word;
    }

    @Override
    public String toString() {
        return count + " " + word;
    }

    static {
        BY_COUNT = (WordCount o1, WordCount o2) -> {
            int r = Integer.compare(o1.count, o2.count);
            if (r == 0) {
                r = o1.word.compareTo(o2.word);
            }
            return r;
        };
    }
}

您的代码将变成：

    List<WordCount> words = new ArrayList<>();  
    words.add(WordCount.parse("9 hello"));
    words.add(WordCount.parse("98 food"));
    words.add(WordCount.parse("105 cat"));
    words.add(WordCount.parse("2514 human"));
    words.add(WordCount.parse("3 pencil"));
    words.sort(WordCount.BY_COUNT.reversed());
    words.forEach((wc) -> {
        System.out.println(wc);
    });

结果如下：

2514 human
105 cat
98 food
9 hello
3 pencil