I am generating random numbers from 1~10, but I want to give number 8 high priority, so that 8 number should generate more times, how can I do this?

Issue

This means the number 8 have high priority, so it will generate more times then other numbers. for example :

• first generate no. 4
• second generate no. 8
• third generate no. 2
• fourth generate no. 8
• fifth generate no. 8

In given example you can see that the number 8 has high priority that`s why it generate more times.

private int getRandom(int _minValue, int _maxValue) {
    Random random = new Random();
    return random.nextInt(_maxValue - _minValue + 1) + _minValue;
}

Solution

A quick way to do this if you only need to increase the weight of a single value, is by generating extra values from Random that you associate with the specific number you want to weigh more. For example, generate 1 to 20 and consider all numbers above the max of 10 as 8.

Here is an example method based on yours, that would take 2 more parameters to determine what number you to weigh more, and how much more you want it to weigh:

private int weightedRandom(int minValue, int maxValue, int weightedNum, int weight) {
    Random random = new Random();
    int randomVal = random.nextInt(maxValue - minValue + weight + 1) + minValue;
    if (randomVal > maxValue) {
        randomVal = weightedNum;
    }
    return randomVal;
}

Tested with below (helper method changed to static to test from main):

public static void main(String[] args) {
    int max = 10;
    int weight = 4;
    int weightedNum = 8;
    int min = 1;

    
    for (int k = 0; k < 50; k++ ) {
        System.out.print(weightedRandom(min, max, weightedNum, weight) + " ");
    }
}

Test Run of 50 method calls:

8 4 8 5 1 1 5 6 8 3 3 9 10 6 10 8 8 8 9 6 8 8 10 2 8 1 5 4 8 2 8 8 6 10 10 4 9 8 8 1 1 10 9 7 7 8 9 7 5 5

Answered By - Nexevis