java - 打乱 Java 流对象列表

Question

这个问题已经有答案了:

Shuffle a list of integers with Java 8 Streams API (8 个回答)

已关闭 3 年前。

我有一个单词列表:List<Word> words

bean Word是:

public class Word {
    private String name;
    private String meaning;
...
}

我想对元素进行洗牌以使其具有以下内容:

来自:

{ name: "day", meaning: "giorno"},
{ name: "year", meaning: "anno"},
{ name: "hour", meaning: "ora"}

致:

{ name: "day", meaning: "ora"},
{ name: "year", meaning: "giorno"},
{ name: "hour", meaning: "anno"}

我已经尝试过这个，但我认为有一个更优雅的解决方案:

private List<Word> shuffle(List<Word> words) {
        List<String> names = words.stream()
                                .map(word -> word.getName())
                                .collect(Collectors.toList());
        List<String> meanings = words.stream()
                                .map(word -> word.getMeaning())
                                .collect(Collectors.toList());
        Collections.shuffle(meanings);

        words = new ArrayList<Word>();
        for(int i = 0; i<names.size(); i++) {
            words.add(new Word(names.get(i), meanings.get(i)));
        }

        return words;
    }

Answer 1

您可以进行就地洗牌。为此，您无需创建额外的 Word 对象。

private void shuffle(List<Word> words) {
    List<String> meanings = words.stream()
            .map(Word::getMeaning)
            .collect(Collectors.toList());
    Collections.shuffle(meanings);

    for(int i = 0; i < words.size(); i++) {
        words.get(i).setMeaning(meanings.get(i));
    }
}