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Java 8 Streams - Collectors.summingInt Examples

Java 8 Streams Java Java API 


java.lang.Objectjava.lang.Objectjava.util.stream.Collectorsjava.util.stream.CollectorsLogicBig

The static method, Collectors.summingInt() returns a Collector which uses a provided mapper function to convert each input element of type T to primitive int, and returns the sum of the resulting integer values.

<T> Collector<T,?,Integer> summingInt(ToIntFunction<? super T> mapper)


Examples


package com.logicbig.example.collectors;

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

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

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

int i = s.collect(Collectors.summingInt(
(BigDecimal::intValue)));
System.out.println("sum: " + i);
}
}

Output

1
2
3
4
5
6
7
8
9
10
sum: 55
Original Post




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