Java BigDecimal、Integer、Long、Double类型数值求最大最小值

淡淡的烟草味﹌ 2022-09-14 09:28 408阅读 0赞

# 1 BigDecimal类型数值求最大最小值 #

## 1.1 for循环实现 ##

List<BigDecimal> list = new ArrayList<>(Arrays.asList(new BigDecimal(1), new BigDecimal(2)));
            BigDecimal max = list.get(0);
            BigDecimal min = list.get(0);
            for (BigDecimal decimal : list) {
                if (max.compareTo(decimal) < 0) {
                    max = decimal;
                }
                if (min.compareTo(decimal) > 0) {
                    min = decimal;
                }
            }

## 1.2 stream().reduce()实现 ##

List<BigDecimal> list = new ArrayList<>(Arrays.asList(new BigDecimal(1), new BigDecimal(2)));
            BigDecimal max = list.stream().reduce(list.get(0), BigDecimal::max);
            BigDecimal min = list.stream().reduce(list.get(0), BigDecimal::min);

## 1.3 stream().max()或stream().min()实现  ##

List<BigDecimal> list = new ArrayList<>(Arrays.asList(new BigDecimal(1), new BigDecimal(2)));
            BigDecimal max = list.stream().max(Comparator.comparing(x -> x)).orElse(null);
            BigDecimal min = list.stream().min(Comparator.comparing(x -> x)).orElse(null);

##  1.4 Collectors.maxBy()或Collectors.minBy()实现  ##

List<BigDecimal> list = new ArrayList<>(Arrays.asList(new BigDecimal(1), new BigDecimal(2)));
            BigDecimal max = list.stream().collect(Collectors.maxBy(Comparator.comparing(x -> x))).orElse(null);
            BigDecimal min = list.stream().collect(Collectors.minBy(Comparator.comparing(x -> x))).orElse(null);

# 2 Integer类型数值求最大最小值 #

##  2.1 for循环实现 ##

List<Integer> list = new ArrayList<>(Arrays.asList(1, 2));
            Integer max = list.get(0);
            Integer min = list.get(0);
            for (Integer num : list) {
                if (num > max) {
                    max = num;
                }
                if (num < min) {
                    min = num;
                }
            }

## 2.2 stream().reduce()实现 ##

List<Integer> list = new ArrayList<>(Arrays.asList(1, 2));
            Integer max = list.stream().reduce(list.get(0), Integer::max);
            Integer min = list.stream().reduce(list.get(0), Integer::min);

## 2.3 Collectors.summarizingInt()实现 ##

List<Integer> list = new ArrayList<>(Arrays.asList(1, 2));
            IntSummaryStatistics intSummaryStatistics = list.stream().collect(Collectors.summarizingInt(x -> x));
            Integer max = intSummaryStatistics.getMax();
            Integer min = intSummaryStatistics.getMin();

## 2.4 stream().max()或stream().min()实现 ##

List<Integer> list = new ArrayList<>(Arrays.asList(1, 2));
            Integer max = list.stream().max(Comparator.comparing(x -> x)).orElse(null);
            Integer min = list.stream().min(Comparator.comparing(x -> x)).orElse(null);

## 2.5 Collectors.maxBy()或Collectors.minBy()实现 ##

List<Integer> list = new ArrayList<>(Arrays.asList(1, 2));
            Integer max = list.stream().collect(Collectors.maxBy(Comparator.comparing(x -> x))).orElse(null);
            Integer min = list.stream().collect(Collectors.minBy(Comparator.comparing(x -> x))).orElse(null);

# 3 Long类型数值求最大最小值 #

## 3.1 for循环实现 ##

List<Long> list = new ArrayList<>(Arrays.asList(1L, 2L));
            Long max = list.get(0);
            Long min = list.get(0);
            for (Long num : list) {
                if (num > max) {
                    max = num;
                }
                if (num < min) {
                    min = num;
                }
            }

## 3.2 stream().reduce()实现  ##

List<Long> list = new ArrayList<>(Arrays.asList(1L, 2L));
            Long max = list.stream().reduce(list.get(0), Long::max);
            Long min = list.stream().reduce(list.get(0), Long::min);

## 3.3 Collectors.summarizingLong()实现 ##

List<Long> list = new ArrayList<>(Arrays.asList(1L, 2L));
            LongSummaryStatistics summaryStatistics = list.stream().collect(Collectors.summarizingLong(x -> x));
            Long max = summaryStatistics.getMax();
            Long min = summaryStatistics.getMin();

## 3.4 stream().max()或stream().min()实现 ##

List<Long> list = new ArrayList<>(Arrays.asList(1L, 2L));
            Long max = list.stream().max(Comparator.comparing(x -> x)).orElse(null);
            Long min = list.stream().min(Comparator.comparing(x -> x)).orElse(null);

## 3.5 Collectors.maxBy()或Collectors.minBy()实现 ##

List<Long> list = new ArrayList<>(Arrays.asList(1L, 2L));
            Long max = list.stream().collect(Collectors.maxBy(Comparator.comparing(x -> x))).orElse(null);
            Long min = list.stream().collect(Collectors.minBy(Comparator.comparing(x -> x))).orElse(null);

# 4 Double类型数值求最大最小值 #

## 4.1 for循环实现 ##

List<Double> list = new ArrayList<>(Arrays.asList(1d, 2d));
            Double max = list.get(0);
            Double min = list.get(0);
            for (Double num : list) {
                if (num > max) {
                    max = num;
                }
                if (num < min) {
                    min = num;
                }
            }

## 4.2 stream().reduce()实现  ##

List<Double> list = new ArrayList<>(Arrays.asList(1d, 2d));
            Double max = list.stream().reduce(list.get(0), Double::max);
            Double min = list.stream().reduce(list.get(0), Double::min);

## 4.3 Collectors.summarizingDouble()实现 ##

List<Double> list = new ArrayList<>(Arrays.asList(1d, 2d));
            DoubleSummaryStatistics summaryStatistics = list.stream().collect(Collectors.summarizingDouble(x -> x));
            Double max = summaryStatistics.getMax();
            Double min = summaryStatistics.getMin();

## 4.4 stream().max()或stream().min()实现  ##

List<Double> list = new ArrayList<>(Arrays.asList(1d, 2d));
            Double max = list.stream().max(Comparator.comparing(x -> x)).orElse(null);
            Double min = list.stream().min(Comparator.comparing(x -> x)).orElse(null);

## 4.5 Collectors.maxBy()或Collectors.minBy()实现 ##

List<Double> list = new ArrayList<>(Arrays.asList(1d, 2d));
            Double max = list.stream().collect(Collectors.maxBy(Comparator.comparing(x -> x))).orElse(null);
            Double min = list.stream().collect(Collectors.minBy(Comparator.comparing(x -> x))).orElse(null);