DoubleSummaryStatistics
open class DoubleSummaryStatistics : DoubleConsumer
kotlin.Any | |
↳ | java.util.DoubleSummaryStatistics |
A state object for collecting statistics such as count, min, max, sum, and average.
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:
<code>DoubleSummaryStatistics stats = doubleStream.collect(DoubleSummaryStatistics::new, DoubleSummaryStatistics::accept, DoubleSummaryStatistics::combine); </code>
DoubleSummaryStatistics
can be used as a reduction target for a stream. For example:
<code>DoubleSummaryStatistics stats = people.stream() .collect(Collectors.summarizingDouble(Person::getWeight)); </code>
Summary
Public constructors | |
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Constructs an empty instance with zero count, zero sum, |
|
DoubleSummaryStatistics(count: Long, min: Double, max: Double, sum: Double) Constructs a non-empty instance with the specified |
Public methods | |
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open Unit |
Records another value into the summary information. |
open Unit |
combine(other: DoubleSummaryStatistics!) Combines the state of another |
Double |
Returns the arithmetic mean of values recorded, or zero if no values have been recorded. |
Long |
getCount() Return the count of values recorded. |
Double |
getMax() Returns the maximum recorded value, |
Double |
getMin() Returns the minimum recorded value, |
Double |
getSum() Returns the sum of values recorded, or zero if no values have been recorded. |
open String |
toString() Returns a non-empty string representation of this object suitable for debugging. |
Inherited functions | |
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Public constructors
DoubleSummaryStatistics
DoubleSummaryStatistics()
Constructs an empty instance with zero count, zero sum, Double.POSITIVE_INFINITY
min, Double.NEGATIVE_INFINITY
max and zero average.
DoubleSummaryStatistics
DoubleSummaryStatistics(
count: Long,
min: Double,
max: Double,
sum: Double)
Constructs a non-empty instance with the specified count
, min
, max
, and sum
.
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:
count >= 0
(min <= max && !isNaN(sum)) || (isNaN(min) && isNaN(max) && isNaN(sum))
Parameters | |
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count |
Long: the count of values |
min |
Double: the minimum value |
max |
Double: the maximum value |
sum |
Double: the sum of all values |
Exceptions | |
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java.lang.IllegalArgumentException |
if the arguments are inconsistent |
Public methods
accept
open fun accept(value: Double): Unit
Records another value into the summary information.
Parameters | |
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value |
Double: the input value |
combine
open fun combine(other: DoubleSummaryStatistics!): Unit
Combines the state of another DoubleSummaryStatistics
into this one.
Parameters | |
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other |
DoubleSummaryStatistics!: another DoubleSummaryStatistics |
Exceptions | |
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java.lang.NullPointerException |
if other is null |
getAverage
fun getAverage(): Double
Returns the arithmetic mean of values recorded, or zero if no values have been recorded.
The computed average can vary numerically and have the special case behavior as computing the sum; see getSum
for details.
Return | |
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Double |
the arithmetic mean of values, or zero if none |
getCount
fun getCount(): Long
Return the count of values recorded.
Return | |
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Long |
the count of values |
getMax
fun getMax(): Double
Returns the maximum recorded value, Double.NaN
if any recorded value was NaN or Double.NEGATIVE_INFINITY
if no values were recorded. Unlike the numerical comparison operators, this method considers negative zero to be strictly smaller than positive zero.
Return | |
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Double |
the maximum recorded value, Double.NaN if any recorded value was NaN or Double.NEGATIVE_INFINITY if no values were recorded |
getMin
fun getMin(): Double
Returns the minimum recorded value, Double.NaN
if any recorded value was NaN or Double.POSITIVE_INFINITY
if no values were recorded. Unlike the numerical comparison operators, this method considers negative zero to be strictly smaller than positive zero.
Return | |
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Double |
the minimum recorded value, Double.NaN if any recorded value was NaN or Double.POSITIVE_INFINITY if no values were recorded |
getSum
fun getSum(): Double
Returns the sum of values recorded, or zero if no values have been recorded.
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:
- If any recorded value is a NaN, then the final sum will be NaN.
- If the recorded values contain one or more infinities, the sum will be infinite or NaN.
- If the recorded values contain infinities of opposite sign, the sum will be NaN.
- If the recorded values contain infinities of one sign and an intermediate sum overflows to an infinity of the opposite sign, the sum may be NaN.
Return | |
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Double |
the sum of values, or zero if none |
toString
open fun toString(): String
Returns a non-empty string representation of this object suitable for debugging. The exact presentation format is unspecified and may vary between implementations and versions.
Return | |
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String |
a string representation of the object. |