Java8中Stream流求最大值最小值

文章目录

• java中各种类型用Stream流求最大值最小值
• • 一、BigDecimal 求最大值和最小值
  • • 1. stream().reduce()实现
    • 2. stream().max()或stream().min()实现
  • 二、Integer 求最大值和最小值
  • • 1. stream().reduce()实现
    • 2. Collectors.summarizingInt()实现
    • 3. stream().max()或stream().min()实现
  • 三、Long 求最大值和最小值
  • • 1. stream().reduce()实现
    • 2. Collectors.summarizingLong()实现
    • 3. stream().max()或stream().min()实现
  • 四、Double 求最大值和最小值
  • • 1. stream().reduce()实现
    • 2. Collectors.summarizingLong()实现
    • 3. stream().max()或stream().min()实现

java中各种类型用Stream流求最大值最小值

一、BigDecimal 求最大值和最小值

1. 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);

2. 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);

二、Integer 求最大值和最小值

1. 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. 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();

3. 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);

三、Long 求最大值和最小值

1. 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);

2. 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. 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);

四、Double 求最大值和最小值

1. 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);

2. Collectors.summarizingLong()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();

3. 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);