Java 8 Streams - Collectors.summarizingLong Examples

The static method, Collectors.summarizingLong() returns a Collector which applies a mapping function to each input element of type T to convert it to primitive long, and returns summary statistics for the resulting long values.


<T> Collector<T,?,LongSummaryStatistics> summarizingLong(ToLongFunction<? super T> mapper)

Examples

package com.logicbig.example.collectors;

import java.math.BigDecimal;
import java.util.DoubleSummaryStatistics;
import java.util.LongSummaryStatistics;
import java.util.stream.Collectors;
import java.util.stream.Stream;

public class SummarizingLongExample {
    public static void main (String[] args) {

        Stream<BigDecimal> s = Stream.iterate(
                            BigDecimal.ONE, bigDecimal ->
                                                bigDecimal.add(BigDecimal.ONE))
                                                 .limit(10).peek(System.out::println);

        LongSummaryStatistics l = s.collect(Collectors.summarizingLong
                                                      (BigDecimal::longValue));
        System.out.println(l);
    }
}

Output

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LongSummaryStatistics{count=10, sum=55, min=1, average=5.500000, max=10}

Original Post

Java 8 Streams - Collectors.summarizingLong Examples

Examples

Output

See Also