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FlexDoc/Javadoc 2.0 Demo Java Doc |
This class is designed to work with (though does not require) streams. For example, you can compute summary statistics on a stream of doubles with:
DoubleSummaryStatistics stats = doubleStream.collect(DoubleSummaryStatistics::new,
DoubleSummaryStatistics::accept,
DoubleSummaryStatistics::combine);
DoubleSummaryStatistics can be used as a reduction target for a stream. For example:
DoubleSummaryStatistics stats = people.stream()
.collect(Collectors.summarizingDouble(Person::getWeight));
This computes, in a single pass, the count of people, as well as the minimum,
maximum, sum, and average of their weights.This implementation does not check for overflow of the count.
Constructor Summary |
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Constructs an empty instance with zero count, zero sum,
Double.POSITIVE_INFINITY min, Double.NEGATIVE_INFINITY
max and zero average.
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DoubleSummaryStatistics(long count, double min, double max, double sum)
Constructs a non-empty instance with the specified count,
min, max, and sum.
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Method Summary |
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void |
accept(double value)
Records another value into the summary information.
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void |
combine(DoubleSummaryStatistics other)
Combines the state of another DoubleSummaryStatistics into this
one.
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final double |
Returns the arithmetic mean of values recorded, or zero if no
values have been recorded.
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final long |
getCount()
Return the count of values recorded.
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final double |
getMax()
Returns the maximum recorded value, Double.NaN if any recorded
value was NaN or Double.NEGATIVE_INFINITY if no values were
recorded.
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final double |
getMin()
Returns the minimum recorded value, Double.NaN if any recorded
value was NaN or Double.POSITIVE_INFINITY if no values were
recorded.
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final double |
getSum()
Returns the sum of values recorded, or zero if no values have been
recorded.
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toString()
Returns a non-empty string representation of this object suitable for
debugging.
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Methods inherited from class java.lang.Object |
Methods inherited from interface java.util.function.DoubleConsumer |
public DoubleSummaryStatistics |
() |
public DoubleSummaryStatistics |
(long count, double min, double max, double sum) |
throws |
If count is zero then the remaining arguments are ignored and an empty instance is constructed.
If the arguments are inconsistent then an IllegalArgumentException is thrown. The necessary consistent argument conditions are:
public void accept |
(double value) |
public void combine |
(DoubleSummaryStatistics other) |
public final long getCount |
() |
public final double getSum |
() |
The value of a floating-point sum is a function both of the input values as well as the order of addition operations. The order of addition operations of this method is intentionally not defined to allow for implementation flexibility to improve the speed and accuracy of the computed result. In particular, this method may be implemented using compensated summation or other technique to reduce the error bound in the numerical sum compared to a simple summation of double values. Because of the unspecified order of operations and the possibility of using differing summation schemes, the output of this method may vary on the same input values.
Various conditions can result in a non-finite sum being computed. This can occur even if the all the recorded values being summed are finite. If any recorded value is non-finite, the sum will be non-finite:
public final double getMin |
() |
public final double getMax |
() |
public final double getAverage |
() |
The computed average can vary numerically and have the special case behavior as computing the sum; see getSum() for details.
public String toString |
() |
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FlexDoc/Javadoc 2.0 Demo Java Doc |