How to Extract Multiple Random Elements from an Array in JavaScript Without Duplicates?

How to Extract Multiple Random Elements from an Array in JavaScript

Problem:

Retrieving a single random element from an array is straightforward using the formula Math.floor(Math.random() * array.length). However, retrieving multiple random elements without duplicates can be challenging.

Solution:

To obtain a specified number of random elements from an array, follow these steps:

1. Shuffle the array using array.sort(() => 0.5 - Math.random()). This line ensures that the elements in the array are randomized.
2. Extract the first n elements from the shuffled array using selected = shuffled.slice(0, n). This line selects the first n elements from the shuffled array.

Example:

Consider the following code:

<code class="javascript">n = 5;
array = Array.from({ length: 50 }, (v, k) => k * 10); // [0,10,20,30,...,490]
var shuffled = array.sort(function () { return 0.5 - Math.random() });
var selected = shuffled.slice(0, n);

document.querySelector('#out').textContent = selected.toString();</code>

This code shuffles an array of 50 numbers and retrieves the first 5 random elements, displaying them in the HTML document.

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