How to Randomly Select Multiple Elements from an Array in JavaScript?

How to Randomly Select Multiple Elements from an Array

JavaScript offers an array element randomization function using Math.floor(Math.random()*items.length). However, this method only selects a single element. For selecting multiple elements, we need a more comprehensive approach.

Solution:

To obtain multiple random elements from an array, we can implement the following two-step process:

1. Shuffle the array to randomize the element order:

   const shuffled = array.sort(() => 0.5 - Math.random());

2. Extract a sub-array of the desired length from the shuffled array:

   let selected = shuffled.slice(0, n);

Demonstration:

In the example code, we declare an array of numbers array and specify the number of elements to extract (n). By shuffling the array and slicing it, we obtain a sub-array selected containing n random elements.

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();

This approach provides a flexible and efficient way to randomly select multiple elements from an array, regardless of its size.

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