Collectors summingDouble (ToDoubleFunction mapper)
Description
Collectors summingDouble(ToDoubleFunction<? super T> mapper)
returns a Collector that produces the sum of a double-valued function applied to the input elements.
Syntax
summingDouble has the following syntax.
public static <T> Collector<T,?,Double> summingDouble(ToDoubleFunction<? super T> mapper)
Example
The following example shows how to use summingDouble.
import java.util.stream.Collectors;
import java.util.stream.Stream;
//from w w w . j a v a 2s . c om
public class Main {
public static void main(String[] args) {
Stream<String> s = Stream.of("1","2","3");
double o = s.collect(Collectors.summingDouble(n->Double.parseDouble(n)));
System.out.println(o);
}
}
The code above generates the following result.
