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);
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