Java 8 IntStream, LongStream and DoubleStream Example
December 31, 2014
IntStream
java.util.stream.IntStream is a sequence of primitive integer values. The aggregate operations like max and average can be performed using sequential and parallel operations.rangeClosed(a,b): The values from a to be are considered by incrementing 1.
range(a,b) : Values from a to b-1 are considered.
sum: Calculates the sum of values.
sorted: Values are sorted.
Find the example of IntStream.
IntStreamDemo.java
package com.concretepage;
import java.util.stream.IntStream;
public class IntStreamDemo {
public static void main(String[] args) {
System.out.println("--Using IntStream.rangeClosed--");
IntStream.rangeClosed(13, 15).map(n->n*n).forEach(s->System.out.print(s +" "));
System.out.println("\n--Using IntStream.range--");
IntStream.range(13,15).map(n->n*n).forEach(s->System.out.print(s +" "));
System.out.println("\n--Sum of range 1 to 10--");
System.out.print(IntStream.rangeClosed(1,10).sum());
System.out.println("\n--Sorted number--");
IntStream.of(13,4,15,2,8).sorted().forEach(s->System.out.print(s +" "));
}
}
--Using IntStream.rangeClosed-- 169 196 225 --Using IntStream.range-- 169 196 --Sum of range 1 to 10-- 55 --Sorted number-- 2 4 8 13 15
LongStream
java.util.stream.LongStream is a sequence of primitive long values and aggregate operations are performed using sequential and parallel operations. Methods are same like IntStream.LongStreamDemo.java
package com.concretepage;
import java.util.stream.LongStream;
public class LongStreamDemo {
public static void main(String[] args) {
System.out.println("--Using LongStream.rangeClosed--");
LongStream.rangeClosed(13, 15).map(n->n*n).forEach(s->System.out.print(s +" "));
System.out.println("\n--Using LongStream.range--");
LongStream.range(13,15).map(n->n*n).forEach(s->System.out.print(s +" "));
System.out.println("\n--Sum of range 1 to 10--");
System.out.print(LongStream.rangeClosed(1,10).sum());
System.out.println("\n--Sorted number--");
LongStream.of(13,4,15,2,8).sorted().forEach(s->System.out.print(s +" "));
}
}
--Using LongStream.rangeClosed-- 169 196 225 --Using LongStream.range-- 169 196 --Sum of range 1 to 10-- 55 --Sorted number-- 2 4 8 13 15
DoubleStream
java.util.stream.DoubleStream is a sequence of primitive double values and aggregate operations are performed using sequential and parallel operations.average: Calculates the average.
max: Finds the max value.
Find the example of DoubleStream.
package com.concretepage;
import java.util.function.DoublePredicate;
import java.util.stream.DoubleStream;
public class DoubleStreamDemo {
public static void main(String[] args) {
System.out.println("--Using DoubleStream.of--");
DoubleStream.of(5.33,2.34,5.32,2.31,3.51).map(d->d*1.5).forEach(s->System.out.print(s +" "));
System.out.println("\n--Using DoubleStream.average--");
double val = DoubleStream.of(12.1,11.2,13.3).average().getAsDouble();
System.out.println(val);
System.out.println("--Using DoubleStream.max--");
val = DoubleStream.of(12.1,11.2,13.3).max().getAsDouble();
System.out.println(val);
System.out.println("--Using DoubleStream.filter--");
DoublePredicate range = d -> d > 12.11 && d < 12.99;
DoubleStream.of(12.1,11.2,12.3).filter(range).forEach(d->System.out.print(d));
}
}
--Using DoubleStream.of-- 7.995 3.51 7.98 3.465 5.265 --Using DoubleStream.average-- 12.200000000000001 --Using DoubleStream.max-- 13.3 --Using DoubleStream.filter-- 12.3
