How to get a random number in one statement from a list of values;

Given the code below I have to find a way to get a random value from the values: 100, 120, 140, 160, 180, 200, 220, 240, 260, 280. The catch is that I have to write a single statement (One semi-colon) that will randomly pick one of the ints and assign it into the random_int variable. Does anyone have any idea how I could create a list or array of the numbers above and pick a random int from the numbers to assign to random_int in a single statement? Thank you for the help!

  public static void main(String[] args) {
    Random random = new Random();
     int random_int;
    // Your single statement goes here
    System.out.println(“Number is: “ + random_int);
    }

Push them all into an array and random the array's index. All can be done in one single statement:

public static void main(String[] args) {
    Random random = new Random();
    int random_int = new int[]{100, 120, 140, 160, 180, 200, 220, 240, 260, 280}[random.nextInt(10)];
    System.out.println("Number is: " + random_int);
}

You can make use of the Arrays class to create a collection from your array

System.out.println(Arrays.asList(100, 120, 140, 160, 180, 200, 220, 240, 260, 280).
                                                          get(new Random().nextInt(10)));

You can do something like:

public static void main(String[] args) {
        Random random = new Random();
        List<Integer> integerList = Arrays.asList(100, 120, 140, 160, 180, 200, 220, 240, 260, 280);
        System.out.println(integerList.get(random.nextInt(integerList.size())));
    }

int random_int = new Random().nextInt(10)*20 + 100;
int random_int = (new Random().nextInt(10) + 5)*20;

nextInt(10) will give 0..9. (9 = (280 - 100)/20).

It is a matter of seeing the regularities in the desired numbers: steps of 20, starting with 100 upto 280.

Could have been an exam question.

public class Foo {

    public static void main(String[] args) {
        for (int i = 0; i < NUMBERS.size(); i++)
            System.out.println(getRandomNumber());
    }

    private static final List<Integer> NUMBERS = Arrays.asList(100, 120, 140, 160, 180, 200, 220, 240, 260, 280);

    public static int getRandomNumber() {
        Collections.shuffle(NUMBERS);
        return NUMBERS.get(0);
    }

}

Given below can be the single statement to do the job:

random_int = List.of(100, 120, 140, 160, 180, 200, 220, 240, 260, 280)
				.get(random.nextInt(List.of(100, 120, 140, 160, 180, 200, 220, 240, 260, 280).size()));

Explanation:

1. Random#nextInt(int bound) returns an int value between 0 (inclusive) and bound (exclusive).
2. List#get(int index) returns the element at the specified position in this list.
3. List#size() returns the number of elements in this list.