`IntStream.range`

Suppose you want to operate on numbers in sequential order: 1, 2, 3. You could create an array and use a for-loop to get these numbers.

Alternatively, you can use IntStream.range with 2 arguments. The IntStream.rangeClosed method, which is almost the same, is also available.

An example

This program demonstrates IntStream.range and IntStream.rangeClosed. It creates the IntStreams and then displays them to the console.

Note Range has an exclusive end. So the second argument is not included in the IntStream that is returned.

Note 2 RangeClosed has an inclusive (closed) end. If the second argument is 15, the 15 is included.

import java.util.Arrays;
import java.util.stream.IntStream;

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

        // Use IntStream.range.
        IntStream range1 = IntStream.range(10, 15);
        System.out.println("Range(10, 15):       " +
            Arrays.toString(range1.toArray()));

        // Use IntStream.rangeClosed.
        IntStream range2 = IntStream.rangeClosed(10, 15);
        System.out.println("RangeClosed(10, 15): " +
            Arrays.toString(range2.toArray()));
    }
}Range(10, 15):       [10, 11, 12, 13, 14]
RangeClosed(10, 15): [10, 11, 12, 13, 14, 15]

Some notes

Range() is a useful method. We can create a Stream and then operate upon it with IntStream-based methods like filter(). This is a powerful approach to solving problems.

A summary

Typically it is a better idea to create a range-based IntStream with range() and rangeClosed(). But an int array, and the Arrays.stream() method, can also be used.