How to Generate Random Doubles in an Array in Java

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Shiv Yadav Feb 02, 2024
Java Java Array Java Random
  1. Generate Random double in a Java Array Using the java.util.Random Class
  2. Generate Random double in a Java Array Using ThreadLocalRandom
How to Generate Random Doubles in an Array in Java

This article will introduce how to generate random doubles in a Java array.

Generate Random double in a Java Array Using the java.util.Random Class

In Java, we utilize the nextDouble() method of the java.util.Random class to generate a random array of doubles. This function returns the next random double value generated by this random number generator.

Example:

import java.util.Random;
public class RandomDoubles {
  public static void main(String[] args) {
    Random rd = new Random();
    double[] array = new double[3];
    for (int i = 0; i < array.length; i++) {
      array[i] = rd.nextDouble();
      System.out.println(array[i]);
    }
  }
}

Here, rd.nextDouble() returns a number between 0 and 1.0.

Output:

0.6281807590035252
0.34456583017282394
0.23684352236085848

Shorter Version

There is a shorter version of doing the same thing as the following.

Example:

import java.util.Random;
public class RandomDoubles {
  public static void main(String[] args) {
    Random rd = new Random();
    double[] array = rd.doubles(5, 10, 100).toArray();
  }
}

Th first argument of rd.doubles method takes the number of random doubles you want in the array. And, the second and third argument takes a minimum and maximum value of range for generating random numbers.

Output:

78.21950288465801 80.12875947698258 94.95442635507693 88.63415507060164 31.283712117527568

Generate Random double in a Java Array Using ThreadLocalRandom

We can also generate random doubles by using ThreadLocalRandom.

Example:

import java.util.concurrent.ThreadLocalRandom;
public class RandomDoubles {
  public static void main(String[] args) {
    double[] randoms = ThreadLocalRandom.current().doubles(5).toArray();
    for (double num : randoms) {
      System.out.println(num);
    }
  }
}

Output:

0.5417255613845797
0.2522145088132569
0.42238415650855565
0.8432309480218088
0.13192651019478996
Author: Shiv Yadav
Shiv Yadav avatar Shiv Yadav avatar

Shiv is a self-driven and passionate Machine learning Learner who is innovative in application design, development, testing, and deployment and provides program requirements into sustainable advanced technical solutions through JavaScript, Python, and other programs for continuous improvement of AI technologies.

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