JavaScript: Randomly arrange or shuffle an array

JavaScript Array: Exercise-17 with Solution

Shuffle Array

Write a JavaScript program to shuffle an array.

Sample Solution:

JavaScript Code:

// Function to shuffle an array using the Fisher-Yates algorithm
function shuffle(arra1) {
    // Initialize variables: ctr is the counter, temp is a temporary variable, index is the random index
    var ctr = arra1.length, temp, index;

    // While there are elements in the array
    while (ctr > 0) {
        // Pick a random index
        index = Math.floor(Math.random() * ctr);
        
        // Decrease ctr by 1
        ctr--;
        
        // Swap the last element with the randomly picked element
        temp = arra1[ctr];
        arra1[ctr] = arra1[index];
        arra1[index] = temp;
    }
    
    // Return the shuffled array
    return arra1;
}

// Original array for testing
var myArray = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9];

// Output the shuffled array
console.log(shuffle(myArray));

Output:

[5,3,0,9,8,2,1,4,7,6]

Flowchart:

ES6 Version:

// Function to shuffle an array using the Fisher-Yates algorithm
const shuffle = (arra1) => {
    // Initialize variables: ctr is the counter, temp is a temporary variable, index is the random index
    let ctr = arra1.length, temp, index;

    // While there are elements in the array
    while (ctr > 0) {
        // Pick a random index
        index = Math.floor(Math.random() * ctr);
        
        // Decrease ctr by 1
        ctr--;
        
        // Swap the last element with the randomly picked element
        temp = arra1[ctr];
        arra1[ctr] = arra1[index];
        arra1[index] = temp;
    }
    
    // Return the shuffled array
    return arra1;
};

// Original array for testing
const myArray = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9];

// Output the shuffled array
console.log(shuffle(myArray));

Live Demo:

See the Pen JavaScript - Randomly arrange or shuffle an array - array-ex- 17 by w3resource (@w3resource) on CodePen.

For more Practice: Solve these Related Problems:

• Write a JavaScript function that shuffles an array using the Fisher-Yates algorithm for unbiased randomization.
• Write a JavaScript function that randomly rearranges an array and verifies randomness over multiple iterations.
• Write a JavaScript function that shuffles an array in place without creating a new array.
• Write a JavaScript function that ensures no element remains in its original index after shuffling.

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