java.util.stream.DoubleStream.count()方法的使用及代码示例

x33g5p2x  于2022-01-18 转载在 其他  
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本文整理了Java中java.util.stream.DoubleStream.count()方法的一些代码示例，展示了DoubleStream.count()的具体用法。这些代码示例主要来源于Github/Stackoverflow/Maven等平台，是从一些精选项目中提取出来的代码，具有较强的参考意义，能在一定程度帮忙到你。DoubleStream.count()方法的具体详情如下：
包路径：java.util.stream.DoubleStream
类名称：DoubleStream
方法名：count

DoubleStream.count介绍

[英]Returns the count of elements in this stream. This is a special case of a reduction and is equivalent to:

return mapToLong(e -> 1L).sum();

This is a terminal operation.
[中]返回此流中元素的计数。这是reduction的一个特例，相当于：

return mapToLong(e -> 1L).sum();

这是一个terminal operation。

代码示例

代码示例来源：origin: speedment/speedment

@Override
public <T> long apply(
  final SqlStreamOptimizerInfo<ENTITY> info,
  final SqlStreamTerminator<ENTITY> sqlStreamTerminator,
  final DoublePipeline pipeline
) {
  requireNonNull(info);
  requireNonNull(sqlStreamTerminator);
  requireNonNull(pipeline);
  return sqlStreamTerminator.optimize(pipeline).getAsDoubleStream().count();
}

代码示例来源：origin: speedment/speedment

default long count(DoublePipeline pipeline) {
  requireNonNull(pipeline);
  return optimize(pipeline).getAsDoubleStream().count();
}

代码示例来源：origin: google/guava

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());
 }
}

代码示例来源：origin: com.davidbracewell/mango

@Override
public long count() {
 return stream.count();
}

代码示例来源：origin: net.dongliu/commons-lang

@Override
public long count() {
  return stream.count();
}

代码示例来源：origin: se.ugli.ugli-commons/ugli-commons

@Override
public long count() {
  // This is a terminal operation
  return evalAndclose(() -> stream.count());
}

代码示例来源：origin: org.apache.plc4x/plc4j-scraper

@Override
public double evaluate(double[] values) throws MathIllegalArgumentException {
  long below = Arrays.stream(values)
    .filter(val -> val <= threshold)
    .count();
  return (double) below / values.length;
}

代码示例来源：origin: cheng-li/pyramid

private static double[] count(double[] input, List<Double> levels){
  double[] count = new double[levels.size()];
  for (int l=0;l<levels.size();l++){
    double level = levels.get(l);
    count[l] = Arrays.stream(input).filter(d->d==level).count();
  }
  for (int i=0;i<count.length;i++){
    count[i] /= input.length;
  }
  return count;
}

代码示例来源：origin: com.speedment.runtime/runtime-core

@Override
public <T> long apply(
  final SqlStreamOptimizerInfo<ENTITY> info,
  final SqlStreamTerminator<ENTITY> sqlStreamTerminator,
  final DoublePipeline pipeline
) {
  requireNonNull(info);
  requireNonNull(sqlStreamTerminator);
  requireNonNull(pipeline);
  return sqlStreamTerminator.optimize(pipeline).getAsDoubleStream().count();
}

代码示例来源：origin: org.apache.plc4x/plc4j-scraper

@Override
public double evaluate(double[] values, int begin, int length) throws MathIllegalArgumentException {
  long below = IntStream.range(begin, length)
    .mapToDouble(i -> values[i])
    .filter(val -> val > threshold)
    .count();
  return 100.0 * below / length;
}

代码示例来源：origin: com.speedment.runtime/runtime-core

default long count(DoublePipeline pipeline) {
  requireNonNull(pipeline);
  return optimize(pipeline).getAsDoubleStream().count();
}

代码示例来源：origin: manoelcampos/cloudsim-plus

/**
 * Creates a a weighted linear regression.
 * @param x the independent variable
 * @param y the dependent variable
 * @param weights the weights to apply to x and y
 * @return
 */
private static SimpleRegression createWeightedLinearRegression(
  final double[] x, final double[] y, final double[] weights)
{
  final double[] weightedX = new double[x.length];
  final double[] weightedY = new double[y.length];
  final long numZeroWeights = Arrays.stream(weights).filter(weight -> weight <= 0).count();
  for (int i = 0; i < x.length; i++) {
    if (numZeroWeights >= 0.4 * weights.length) {
      // See: http://www.ncsu.edu/crsc/events/ugw07/Presentations/Crooks_Qiao/Crooks_Qiao_Alt_Presentation.pdf
      weightedX[i] = Math.sqrt(weights[i]) * x[i];
      weightedY[i] = Math.sqrt(weights[i]) * y[i];
    } else {
      weightedX[i] = x[i];
      weightedY[i] = y[i];
    }
  }
  return createLinearRegression(weightedX, weightedY);
}

代码示例来源：origin: padreati/rapaio

@Override
  public String summary() {
    StringBuilder sb = new StringBuilder();
    sb.append("\n > Kolmogorov-Smirnoff 1-sample test\n");

    int ties = (int) (v.rowCount() - v.stream().mapToDouble().distinct().count());
    sb.append(String.format("sample size: %d, ties: %d\n", v.rowCount(), ties));
    if (ties > 0)
      sb.append(" (warning: p-values will not be exact because of ties)\n");

    sb.append(String.format("densities: %s\n", cdf.name()));
    sb.append("D statistic: ").append(floatFlex(D)).append("\n");
    sb.append("p-value: ").append(floatFlex(pValue)).append(" ").append(Format.pValueStars(pValue)).append("\n");
    sb.append("\n");
    return sb.toString();
  }
}

代码示例来源：origin: padreati/rapaio

@Override
  public String summary() {
    StringBuilder sb = new StringBuilder();
    sb.append("\n > Kolmogorov-Smirnoff 2-sample test\n");

    int ties1 = (int) (v1.rowCount() - v1.stream().mapToDouble().distinct().count());
    int ties2 = (int) (v2.rowCount() - v2.stream().mapToDouble().distinct().count());
    sb.append(String.format("first sample size: %d, ties: %d\n",
        v1.rowCount(), ties1));
    sb.append(String.format("second sample size: %d, ties: %d\n",
        v2.rowCount(), ties2));
    if (ties1 + ties2 > 0)
      sb.append(" (warning: p-values will not be exact because of ties)\n");

    sb.append(String.format("D statistic: %.6f\n", D));
    sb.append(String.format("p-value: %.16f %s\n", pValue, Format.pValueStars(pValue)));
    sb.append("\n");
    return sb.toString();
  }
}

代码示例来源：origin: one.util/streamex

@Override
public long count() {
  if (context.fjp != null)
    return context.terminate(stream()::count);
  return stream().count();
}

代码示例来源：origin: sorz/TinyKeePass

public EntryQueryRelevance(Entry entry, String[] keywords) {
  this.entry = entry;
  double[] ranks = Arrays.stream(keywords).mapToDouble(w ->
      fieldScore(entry.getTitle(), w) * WEIGHT_KW_IN_TITLE +
          fieldScore(entry.getUsername(), w) * WEIGHT_KW_IN_USERNAME +
          fieldScore(entry.getNotes(), w) * WEIGHT_KW_IN_NOTES +
          fieldScore(entry.getTags(), w) * WEIGHT_KW_IN_TAGS +
          fieldScore(entry.getUrl(), w) * WEIGHT_KW_IN_URL).toArray();
  rank = Arrays.stream(ranks).sum();
  unrelatedKeywords = (int) Arrays.stream(ranks).filter(r -> r == 0).count();
}

代码示例来源：origin: OpenGamma/Strata

public void test_emptySeries() {
 LocalDateDoubleTimeSeries test = LocalDateDoubleTimeSeries.empty();
 assertEquals(test.isEmpty(), true);
 assertEquals(test.size(), 0);
 assertEquals(test.containsDate(DATE_2010_01_01), false);
 assertEquals(test.containsDate(DATE_2011_01_01), false);
 assertEquals(test.containsDate(DATE_2012_01_01), false);
 assertEquals(test.get(DATE_2010_01_01), OptionalDouble.empty());
 assertEquals(test.get(DATE_2011_01_01), OptionalDouble.empty());
 assertEquals(test.get(DATE_2012_01_01), OptionalDouble.empty());
 assertEquals(test, LocalDateDoubleTimeSeries.builder().putAll(dates(), values()).build());
 assertEquals(test.dates().count(), 0);
 assertEquals(test.values().count(), 0);
}

代码示例来源：origin: OpenGamma/Strata

public void flatVolTest() {
 double tol = 2.0e-2;
 double constantVol = 0.15;
 ConstantSurface impliedVolSurface = ConstantSurface.of("impliedVol", constantVol);
 Function<Double, Double> zeroRate = new Function<Double, Double>() {
  @Override
  public Double apply(Double x) {
   return 0.05d;
  }
 };
 Function<Double, Double> zeroRate1 = new Function<Double, Double>() {
  @Override
  public Double apply(Double x) {
   return 0.02d;
  }
 };
 ImpliedTrinomialTreeLocalVolatilityCalculator calc =
   new ImpliedTrinomialTreeLocalVolatilityCalculator(45, 1d, INTERP_TIMESQ_LINEAR);
 InterpolatedNodalSurface localVolSurface =
   calc.localVolatilityFromImpliedVolatility(impliedVolSurface, 100d, zeroRate, zeroRate1);
 assertEquals(localVolSurface.getZValues().stream().filter(d -> !DoubleMath.fuzzyEquals(d, constantVol, tol)).count(), 0);
}

代码示例来源：origin: com.google.guava/guava-tests

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());
 }
}

代码示例来源：origin: OpenGamma/Strata

public void flatVolPriceTest() {
 double tol = 2.0e-2;
 double constantVol = 0.15;
 double spot = 100d;
 double maxTime = 1d;
 int nSteps = 9;
 ConstantSurface impliedVolSurface = ConstantSurface.of("impliedVol", constantVol);
 Function<Double, Double> zeroRate = new Function<Double, Double>() {
  @Override
  public Double apply(Double x) {
   return 0d;
  }
 };
 Function<DoublesPair, ValueDerivatives> func = new Function<DoublesPair, ValueDerivatives>() {
  @Override
  public ValueDerivatives apply(DoublesPair x) {
   double price = BlackFormulaRepository.price(spot, x.getSecond(), x.getFirst(), constantVol, true);
   return ValueDerivatives.of(price, DoubleArray.EMPTY);
  }
 };
 DeformedSurface priceSurface = DeformedSurface.of(DefaultSurfaceMetadata.of("price"), impliedVolSurface, func);
 ImpliedTrinomialTreeLocalVolatilityCalculator calc =
   new ImpliedTrinomialTreeLocalVolatilityCalculator(nSteps, maxTime, INTERP_TIMESQ_LINEAR);
 InterpolatedNodalSurface localVolSurface = calc.localVolatilityFromPrice(priceSurface, spot, zeroRate, zeroRate);
 assertEquals(localVolSurface.getZValues().stream().filter(d -> !DoubleMath.fuzzyEquals(d, constantVol, tol)).count(), 0);
}

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