Pick a random element from an array in JavaScript

 In this tutorial, we will learn how to pick a random element from an array in JavaScript. It is essential to know because this is a very common type of operation you will do with the array. For example generating random numbers from 1 to 6 for a dice game, selecting random numbers, etc.

To do this task you need to know the following methods in JavaScript:

  • Math.random(): returns a random number between 0 and 1,1 is not included.
  • Math.floor(): rounds down the number and returns the largest integer equal to or less than a given integer.
  • array.length: it returns the number of elements in the array.

Steps to follow:

  • Define the array and pass it to function random_no.
  • We use Math.random() to generate a random number and then we multiply with array length to get a number between (0-array length).
  • Later we use Math.floor to get the nearest integer value.
  • var random_number is then used to access the random index of the array.

Example:

function random_no(numbers) {

    // get random number
    var random_number = Math.floor(Math.random() * numbers_array.length);

    // access the element
    const element = numbers_array[random_number];

    return element;
}

const numbers_array = [122, 202, 985, 889];

const result = random_no(numbers_array);
const result2=random_no(numbers_array);
console.log(result);
console.log(result2);
OUTPUT:

985
202

Hence, every time we run the function a random element is generated.

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