Java DoubleSummaryStatistics类代码示例

import java.util.DoubleSummaryStatistics; //导入依赖的package包/类
public void testEquivalentStreams() {
  // For datasets of many double values created from an array, we test many combinations of finite
  // and non-finite values:
  for (ManyValues values : ALL_MANY_VALUES) {
    double[] array = values.asArray();
    Stats stats = Stats.of(array);
    // instance methods on Stats vs on instance methods on DoubleStream
    assertThat(stats.count()).isEqualTo(stream(array).count());
    assertEquivalent(stats.mean(), stream(array).average().getAsDouble());
    assertEquivalent(stats.sum(), stream(array).sum());
    assertEquivalent(stats.max(), stream(array).max().getAsDouble());
    assertEquivalent(stats.min(), stream(array).min().getAsDouble());
    // static method on Stats vs on instance method on DoubleStream
    assertEquivalent(Stats.meanOf(array), stream(array).average().getAsDouble());
    // instance methods on Stats vs instance methods on DoubleSummaryStatistics
    DoubleSummaryStatistics streamStats = stream(array).summaryStatistics();
    assertThat(stats.count()).isEqualTo(streamStats.getCount());
    assertEquivalent(stats.mean(), streamStats.getAverage());
    assertEquivalent(stats.sum(), streamStats.getSum());
    assertEquivalent(stats.max(), streamStats.getMax());
    assertEquivalent(stats.min(), streamStats.getMin());
  }
}
 

import java.util.DoubleSummaryStatistics; //导入依赖的package包/类
private double getMinOfMdBottom(ObjMudLog mudLog) {
    List<CsGeologyInterval> geologyIntervals = mudLog.getGeologyInterval();
    DoubleSummaryStatistics summaryStat = geologyIntervals.stream()
                                          .map(CsGeologyInterval::getMdBottom)
                                          .mapToDouble(MeasuredDepthCoord::getValue)
                                          .summaryStatistics();

    double mdMax = -1;
    for (CsGeologyInterval geologyInterval : geologyIntervals) {
        if (geologyInterval.getMdBottom() != null) {
            double value = geologyInterval.getMdBottom().getValue();
            if (mdMax < value) {
                mdMax = value;
            }
        }
    }
    return mdMax;
}
 

import java.util.DoubleSummaryStatistics; //导入依赖的package包/类
public void testDoubleStatistics() {
    List<DoubleSummaryStatistics> instances = new ArrayList<>();
    instances.add(countTo(1000).stream().collect(Collectors.summarizingDouble(i -> i)));
    instances.add(countTo(1000).stream().mapToDouble(i -> i).summaryStatistics());
    instances.add(countTo(1000).stream().mapToDouble(i -> i).collect(DoubleSummaryStatistics::new,
                                                                     DoubleSummaryStatistics::accept,
                                                                     DoubleSummaryStatistics::combine));
    instances.add(countTo(1000).parallelStream().collect(Collectors.summarizingDouble(i -> i)));
    instances.add(countTo(1000).parallelStream().mapToDouble(i -> i).summaryStatistics());
    instances.add(countTo(1000).parallelStream().mapToDouble(i -> i).collect(DoubleSummaryStatistics::new,
                                                                             DoubleSummaryStatistics::accept,
                                                                             DoubleSummaryStatistics::combine));

    for (DoubleSummaryStatistics stats : instances) {
        assertEquals(stats.getCount(), 1000);
        assertEquals(stats.getSum(), (double) countTo(1000).stream().mapToInt(i -> i).sum());
        assertEquals(stats.getAverage(), stats.getSum() / stats.getCount());
        assertEquals(stats.getMax(), 1000.0);
        assertEquals(stats.getMin(), 1.0);
    }
}
 

import java.util.DoubleSummaryStatistics; //导入依赖的package包/类
@Override
public <S> void selectSolutions(Generation<S> generation, GenerationSelectorConfiguration configuration) {

  int selectionSize = (int) Math.round(generation.getSolutions().size() * configuration.getSelectionRatio());
  DoubleSummaryStatistics statistics = calculateFitnessStatistics(generation);

  Random random = new Random(configuration.getRandomSeed());
  while (!isSelectionSizeReached(selectionSize, generation)) {
    for (S solution : generation.getSolutions()) {
      if (selectSolution(solution, generation, random, statistics)) {
        generation.selectSolution(solution);

        if (isSelectionSizeReached(selectionSize, generation)) {
          break;
        }
      }
    }
  }

}
 

import java.util.DoubleSummaryStatistics; //导入依赖的package包/类
private void updateFitnesses(FishState simState) {
    ObservableList<Fisher> fishers = simState.getFishers();
    DoubleSummaryStatistics statistics[] =
            new DoubleSummaryStatistics[lastObservedFitnesses.length];
    Arrays.setAll(statistics, value -> new DoubleSummaryStatistics());
    //get each fishers' utility
    for(Fisher fisher : fishers)
    {

        int index = ((ReplicatorDrivenDestinationStrategy) fisher.getDestinationStrategy()).getStrategyIndex();
        statistics[index].accept(objectiveFunction.computeCurrentFitness(fisher, fisher));
    }
    for(int i=0; i<options.size(); i++)
    {
        lastObservedFitnesses[i] = statistics[i].getAverage();


    }
}
 

import java.util.DoubleSummaryStatistics; //导入依赖的package包/类
private void addDataGatherers(FishState state) {


        //first add data gatherers
        state.getYearlyDataSet().registerGatherer("Average Prediction Error",
                                                  model -> {
            double size =model.getFishers().size();
            if(size == 0)
                return Double.NaN;
            else
            {
                double total = 0;
                for(Fisher fisher1 : state.getFishers()) {
                    DoubleSummaryStatistics errors = new DoubleSummaryStatistics();
                    for(Double error : ((HeatmapDestinationStrategy) fisher1.getDestinationStrategy()).getErrors())
                        errors.accept(error);
                    total += errors.getAverage();
                }
                return total/size;
            }
        }, Double.NaN);

    }
 

import java.util.DoubleSummaryStatistics; //导入依赖的package包/类
private void addDataGatherers(FishState state) {


        //first add data gatherers
        state.getYearlyDataSet().registerGatherer("Average Prediction Error",
                                                  model -> {
                                                      double size =model.getFishers().size();
                                                      if(size == 0)
                                                          return Double.NaN;
                                                      else
                                                      {
                                                          double total = 0;
                                                          for(Fisher fisher1 : state.getFishers()) {
                                                              DoubleSummaryStatistics errors = new DoubleSummaryStatistics();
                                                              for(Double error : ((HeatmapDestinationStrategy) fisher1.getDestinationStrategy()).getErrors())
                                                                  errors.accept(error);
                                                              total += errors.getAverage();
                                                          }
                                                          return total/size;
                                                      }
                                                  }, Double.NaN);

    }
 

import java.util.DoubleSummaryStatistics; //导入依赖的package包/类
public MetaScores(List<Double> scores) {
  // A meta alert could be entirely alerts with no values.
  DoubleSummaryStatistics stats = scores
      .stream()
      .mapToDouble(a -> a)
      .summaryStatistics();
  metaScores.put("max", stats.getMax());
  metaScores.put("min", stats.getMin());
  metaScores.put("average", stats.getAverage());
  metaScores.put("count", stats.getCount());
  metaScores.put("sum", stats.getSum());

  // median isn't in the stats summary
  double[] arr = scores
      .stream()
      .mapToDouble(d -> d)
      .toArray();
  metaScores.put("median", new Median().evaluate(arr));
}
 

import java.util.DoubleSummaryStatistics; //导入依赖的package包/类
@Test
public void gauges() {
  Registry r = newRegistry(true, 10000);
  r.gauge(r.createId("foo", "a", "1")).set(1.0);
  r.gauge(r.createId("foo", "a", "2")).set(2.0);
  r.gauge(r.createId("bar")).set(7.0);

  Assert.assertEquals(3, r.gauges().count());

  final DoubleSummaryStatistics valueSummary = r.gauges()
      .filter(Functions.nameEquals("foo"))
      .collect(Collectors.summarizingDouble(Gauge::value));
  Assert.assertEquals(2, valueSummary.getCount());
  Assert.assertEquals(3.0, valueSummary.getSum(), 1e-12);
  Assert.assertEquals(1.5, valueSummary.getAverage(), 1e-12);
}
 

import java.util.DoubleSummaryStatistics; //导入依赖的package包/类
@Test
public void double_summary_stats_with_stream() {

	DoubleSummaryStatistics stats = companies.stream()
			.mapToDouble((x) -> x.getRevenue()).summaryStatistics();

	// average
	assertEquals(109.9425, stats.getAverage(), 0);

	// count
	assertEquals(4, stats.getCount(), 0);

	// max
	assertEquals(184.9, stats.getMax(), 0);
	
	// min
	assertEquals(12.1, stats.getMin(), 0);

	// sum
	assertEquals(439.77, stats.getSum(), 0);
}
 

import java.util.DoubleSummaryStatistics; //导入依赖的package包/类
@Test
public void double_summary_stats_stream_reduction_target() {

	DoubleSummaryStatistics stats = companies.stream().collect(
			Collectors.summarizingDouble(Company::getRevenue));

	// average
	assertEquals(109.9425, stats.getAverage(), 0);

	// count
	assertEquals(4, stats.getCount(), 0);

	// max
	assertEquals(184.9, stats.getMax(), 0);
	
	// min
	assertEquals(12.1, stats.getMin(), 0);

	// sum
	assertEquals(439.77, stats.getSum(), 0);
}
 

import java.util.DoubleSummaryStatistics; //导入依赖的package包/类
public static void main(String[] args) throws IOException {

		Path salesDataPath = Paths
				.get("src/main/resources/com/levelup/java/exercises/beginner/SalesData.txt")
				.toAbsolutePath();

		//read all lines into a list of strings 
		List<String> fileByLines = java.nio.file.Files
				.readAllLines(salesDataPath);

		//convert each string into a DoubleSummaryStatistics object
		List<DoubleSummaryStatistics> weeksSummary = new ArrayList<>();
		for (String row : fileByLines) {
			// split on comma, map to double
			weeksSummary.add(Arrays.stream(row.split(","))
					.mapToDouble(Double::valueOf).summaryStatistics());
		}

		displayWeeklyStats(weeksSummary);
		displaySummaryResults(weeksSummary);

	}
 

import java.util.DoubleSummaryStatistics; //导入依赖的package包/类
public static void displaySummaryResults(
		List<DoubleSummaryStatistics> weeksSummary) {

	System.out.println("Total sales for all weeks: $"
			+ weeksSummary.stream().mapToDouble(p -> p.getSum()).sum());

	System.out.println("Average weekly sales: $"
			+ weeksSummary.stream().mapToDouble(p -> p.getSum()).average()
					.getAsDouble());

	System.out.println("The highest sales was $"
			+ weeksSummary.stream().mapToDouble(p -> p.getSum()).max()
					.getAsDouble());

	System.out.println("The lowest sales were made during "
			+ weeksSummary.stream().mapToDouble(p -> p.getSum()).min()
					.getAsDouble());

}
 

import java.util.DoubleSummaryStatistics; //导入依赖的package包/类
public static void main(String[] args) {

		// Create a Scanner object for keyboard input.
		Scanner keyboard = new Scanner(System.in);

		// Get a string of digits.
		System.out.print("Enter a string of digits: ");
		String input = keyboard.nextLine();

		// close keyboard
		keyboard.close();

		DoubleSummaryStatistics summaryStats = Stream.of(input.split(""))
				.mapToDouble(Double::valueOf).summaryStatistics();

		System.out.println("The sum of numbers " + summaryStats.getSum());
		System.out.println("The highest digit is " + summaryStats.getMax());
		System.out.println("The lowest digit is " + summaryStats.getMin());
	}
 

import java.util.DoubleSummaryStatistics; //导入依赖的package包/类
@Benchmark
public Object[] combinedStatisticsJDK_parallel()
{
    DoubleSummaryStatistics stats1 =
            Person.getJDKPeople().parallelStream().mapToDouble(Person::getHeightInInches).summaryStatistics();
    DoubleSummaryStatistics stats2 =
            Person.getJDKPeople().parallelStream().mapToDouble(Person::getWeightInPounds).summaryStatistics();
    IntSummaryStatistics stats3 =
            Person.getJDKPeople().parallelStream().mapToInt(Person::getAge).summaryStatistics();
    return new Object[]{stats1, stats2, stats3};
}