Utilizing Math.random to extract unique names from an array without any duplicates

Question

Utilizing Math.random to extract unique names from an array without any duplicates

I have a task to select three unique names from an array and store them in a new array. However, I am facing an issue where the same names keep getting randomized instead of finding new ones.

If you want to see the code in action, check out this jsfiddle script.

Code:

findStudentBtn.onclick = findStudent;

function findStudent() {
    var studArray = ["John","Daniel","Hans","Lars","Tom","Amanda","Jane","Sarah"];
    for (i=0; i<3; i++) {
        if (i === 1) {
            var randomStud1 = studArray[Math.floor(Math.random() * studArray.length)];
            msg8.innerHTML += randomStud1 + ", ";
        }
        if (i === 2) {
            var randomStud2 = studArray[Math.floor(Math.random() * studArray.length)];
            msg8.innerHTML += randomStud2 + ", ";
        }
        if (i === 3) {
            var randomStud3 = studArray[Math.floor(Math.random() * studArray.length)];
            msg8.innerHTML += randomStud3 + ", ";
        }

        if (randomStud1 == randomStud2 || randomStud2 == randomStud3 || randomStud1 == randomStud3){
            msg8.innerHTML = "";
            findStudent();
        } 
    }
}

javascript arrays math random

Answer 1

Answer №1

If you're curious about the solution but don't want to navigate to the jsfiddle, here's the script I implemented.

findStudentBtn.onclick = function(){
    findStudent();
};

var r_stud = ["John","Daniel","Hans","Lars","Tom","Amanda","Jane","Sarah"];
var r_rndm = [];
var r_newr = [];

function getStudent(){

    //Handling cases where available choices are insufficient for selecting 3 students.
    if(r_rndm.length == r_stud.length){
        //Resetting the array of randomly selected students
        r_rndm = [];
        return r_newr;
    }

    //Selecting a student at random
    var i_randomStudent = Math.floor(r_stud.length * Math.random());
    var s_randomStudent = r_stud[i_randomStudent];

    if(r_rndm.indexOf(s_randomStudent) >= 0){
        //If the student has already been selected, try again.
        getStudent();
    }else{
        //Adding the student to both new and all-time selections
        r_rndm.push(s_randomStudent);
        r_newr.push(s_randomStudent);

        //Returning the updated array
        return r_newr;
    }

};

function findStudent(){

    //Reseting the new array.
    r_newr = [];
    for(i = 0; i < 3; i++){
        getStudent();
    };

    //Printing the contents of the new array to console.
    console.log(r_newr);

    for(i = 0; i < r_newr.length; i++){
        separator = (i == r_newr.length - 1 && r_rndm.length == 0 ) ? '' : ', ';
        msg8.innerHTML += r_newr[i] + separator;
    }

};

Answer 2

If you're curious about the solution but don't want to navigate to the jsfiddle, here's the script I implemented.

findStudentBtn.onclick = function(){
    findStudent();
};

var r_stud = ["John","Daniel","Hans","Lars","Tom","Amanda","Jane","Sarah"];
var r_rndm = [];
var r_newr = [];

function getStudent(){

    //Handling cases where available choices are insufficient for selecting 3 students.
    if(r_rndm.length == r_stud.length){
        //Resetting the array of randomly selected students
        r_rndm = [];
        return r_newr;
    }

    //Selecting a student at random
    var i_randomStudent = Math.floor(r_stud.length * Math.random());
    var s_randomStudent = r_stud[i_randomStudent];

    if(r_rndm.indexOf(s_randomStudent) >= 0){
        //If the student has already been selected, try again.
        getStudent();
    }else{
        //Adding the student to both new and all-time selections
        r_rndm.push(s_randomStudent);
        r_newr.push(s_randomStudent);

        //Returning the updated array
        return r_newr;
    }

};

function findStudent(){

    //Reseting the new array.
    r_newr = [];
    for(i = 0; i < 3; i++){
        getStudent();
    };

    //Printing the contents of the new array to console.
    console.log(r_newr);

    for(i = 0; i < r_newr.length; i++){
        separator = (i == r_newr.length - 1 && r_rndm.length == 0 ) ? '' : ', ';
        msg8.innerHTML += r_newr[i] + separator;
    }

};

Utilizing Math.random to extract unique names from an array without any duplicates

Answer №1

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