排序后计算排名

r囧r小猫 2024-02-05 19:03 45阅读 0赞

排序后计算排名

解决方案1/**
         * 计算分数排名
         * @param allFullScores
         */
        public void calculateScoreRank(List<StudentSubjectFullScoreDto> allFullScores) {
        
            Map<Long, StudentSubjectFullScoreDto> stuMap = allFullScores.stream().collect(Collectors.toMap(StudentSubjectFullScoreDto::getStuId, StudentSubjectFullScoreDto->StudentSubjectFullScoreDto));
            //过滤掉不统计的数据，这些数据不参与排名
            List<StudentSubjectFullScoreDto> scoreRankList = allFullScores.stream().filter(t -> t.getStatisticsStatus() == CommonConst.TYPE_STATISTICS_ENABLE).collect(Collectors.toList());
            //按学生单科成绩总分倒序排列
            scoreRankList.sort(Comparator.comparingDouble(StudentSubjectFullScoreDto::getSumScore).reversed());
            //按分数分组，统计个数
            Map<Double, Long> scoreMap = scoreRankList.stream().collect(Collectors.groupingBy(StudentSubjectFullScoreDto::getSumScore, Collectors.counting()));
            //初始值名次
            int rank = 1;
            double scoreRate = 1.0;	//此处不需要删除即可
            for (int i = 0; i < scoreRankList.size(); i++) {
        
                //得到相同分数的个数
                Long count = scoreMap.get(scoreRankList.get(i).getSumScore());
                scoreRate=new BigDecimal(scoreRankList.size() - rank).divide(new BigDecimal(scoreRankList.size()), 2, BigDecimal.ROUND_HALF_UP).doubleValue();
                if (count == 1) {
        
                    StudentSubjectFullScoreDto copyDto = scoreRankList.get(i);
                    StudentSubjectFullScoreDto sourceDto = stuMap.get(copyDto.getStuId());
                    sourceDto.setScoreRank(rank++) ;
                    sourceDto.setScoreRankRate(scoreRate);
                }else {
        
                    //总分相同，名次相同
                    for (int j = 0; j < count; j++) {
        
                        StudentSubjectFullScoreDto copyDto = scoreRankList.get(i+j);
                        StudentSubjectFullScoreDto sourceDto = stuMap.get(copyDto.getStuId());
                        sourceDto.setScoreRank(rank);
                        sourceDto.setScoreRankRate(scoreRate);
                    }
                    //排名还需要按人数顺序数他是第几个
                    rank= (int) (rank+count);
                    //连续n个相同的总分，排名一样
                    i = (int) (i + count -1);
                }
            }
        }

解决方案2

/**
     * 排序：把不同成绩保存map中，最后实体类根据map的key找到排名 存入实体排名里面，前端取值。
     * @return
     */
    public static Map<Double,Integer> rankScore(List<DeductPersonVO> stus) {
        
        Map<Double,Integer> map = new HashMap<>();
        List<Map.Entry<Double, List<DeductPersonVO>>> list = stus.stream().collect(Collectors.groupingBy(DeductPersonVO::getDeductScore)).entrySet()
                .stream().sorted((s1, s2) -> -Double.compare(s1.getKey(), s2.getKey())).collect(Collectors.toList());
        int index = 1;
        for (Map.Entry<Double, List<DeductPersonVO>> entry : list) {
        
     
            map.put(entry.getKey(),index);
            entry.getValue().forEach((s) -> System.out.print("  " + s.getDeductScore()));
            System.out.println();
            index++;
        }
        return map;
    }

取出值存入实体

Map<Double,Integer> rankMap2 = rankScore(personList);
    personList.stream().forEach(bean -> {
        
        bean.setRank(rankMap2.get(bean.getDeductScore()));
    });

其他参考：

//该方法可用于分数成绩排名计算操作
     //传入需要处理的用户成绩集合和分数
    public int getClassRank(List<UserExamScoreVo> list,double userScore){
        
        ArrayList<Double> arrayList = new ArrayList();
        Map map = new HashMap();
        //将需要排序的字段放入集合
        for(int p = 0; p < list.size(); p++){
        
            arrayList.add( Double.valueOf(list.get(p).getScore()));
        }
        //用户成绩为key，循坏下标为value生成map
        for (int i = 0; i < arrayList.size() ; i++) {
        
            if(i == 0){
        
                map.put(arrayList.get(0),0 + 1);
            }
            if(!map.containsKey(arrayList.get(i))){
        
                map.put(arrayList.get(i),i+1);
            }
        }
        //从map中取得对应的位置
        int rank = (int) map.get(userScore);
        return rank;
    }

//先地区在同名分组
    User user1 = new User("zhangsan", "beijing", 10);
    User user2 = new User("zhangsan", "beijing", 20);
    User user3 = new User("lisi", "shanghai", 30);
    List<User> list = new ArrayList<User>();
    list.add(user1);
    list.add(user2);
    list.add(user3);
    Map<String, Map<String, List<User>>> collect
            = list.stream().collect(
                    Collectors.groupingBy(
                            User::getAddress, Collectors.groupingBy(User::getName)
                    )
    );
    System.out.println(collect);