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I have an array like this:
var arr1 = ["a", "b", "c", "d"]; How can I randomize / shuffle it?
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Write the function shuffle(array) that shuffles (randomly reorders) elements of the array. Multiple runs of shuffle may lead to different orders of elements. For instance: let arr = [1, 2, 3]; shuffle(arr); // arr = [3, 2, 1] shuffle(arr); // arr = [2, 1, 3] shuffle(arr); // arr = [3, 1, 2] // ...
Shuffle Array using Random Class We can iterate through the array elements in a for loop. Then, we use the Random class to generate a random index number. Then swap the current index element with the randomly generated index element. At the end of the for loop, we will have a randomly shuffled array.
A JavaScript array elements can be shuffled by using the sort() method. The JavaScript Array sort() method is used to sort the elements of an array. The method accepts a comparison function and performs a sort based on the value returned by that function.
The de-facto unbiased shuffle algorithm is the Fisher-Yates (aka Knuth) Shuffle.
You can see a great visualization here (and the original post linked to this)
function shuffle(array) { let currentIndex = array.length, randomIndex; // While there remain elements to shuffle... while (currentIndex != 0) { // Pick a remaining element... randomIndex = Math.floor(Math.random() * currentIndex); currentIndex--; // And swap it with the current element. [array[currentIndex], array[randomIndex]] = [ array[randomIndex], array[currentIndex]]; } return array; } // Used like so var arr = [2, 11, 37, 42]; shuffle(arr); console.log(arr);Some more info about the algorithm used.
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