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Using an array element only once

I am new to JavaScript, and I would like to get three random elements from my array, which should be different. I already managed to get three different elements, then I tried to use one element only once using the split method. But apparently this does not work, there are probably a lot of mistakes, as this is one of my first scenarios. He also sometimes says "undefined".

http://jsfiddle.net/t4mtpm50/

HTML:

<span id="tot1"></span>, <span id="tot2"> und </span> und <span id="tot3"></span>

JavaScript:

function getNumber() {
    random = Math.floor(Math.random() * students.length);
    students.splice(random,1);
    return random;
}

students = new Array("Paul", "Jan", "Fabian D.", "Fabian K.", "Lennard", 
                            "Robin", "Angelique", "Joyce", "Sarah", "Ajlin",
                            "Enes", "Leon", "Boran", "Joshua")    

getNumber();
tot1 = students[random];
getNumber();
tot2 = students[random];
getNumber();
tot3 = students[random];

document.getElementById('tot1').innerHTML = tot1;
document.getElementById('tot2').innerHTML = tot2;
document.getElementById('tot3').innerHTML = tot3;
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4 answers

.splice(), , random :

var students = [ "Paul", "Jan", "Fabian D." ];
var random = 1;

console.log(students[random]); // "Jan"

students.splice(random, 1);

console.log(students);         // [ "Paul", "Fabian D." ]
console.log(students[random]); // "Fabian D."

" " undefined ", , random :

var students = [ "Paul", "Jan", "Fabian D." ];
var random = 2;

console.log(students[random]); // "Fabian D."

students.splice(random, 1);

console.log(students);         // [ "Paul", "Jan" ]
console.log(students[random]); // undefined, random is now out-of-bounds at 2

.splice(), , getNumber(), , :

function getStudent() {
    var random = Math.floor(Math.random() * students.length);
    return students.splice(random, 1)[0]; // return the 1st and only removed element
}

var tot1 = getStudent(); // "Fabian D."
var tot2 = getStudent(); // "Enes"
var tot3 = getStudent(); // "Joyce"

http://jsfiddle.net/6gox6L1t/

+7

, , :

function getStudent(students) {
    var random = Math.floor(Math.random() * (students.length));
    var my_student = students.splice(random,1);
    return my_student;
}

var students = new Array("Paul", "Jan", "Fabian D.", "Fabian K.", "Lennard", 
                            "Robin", "Angelique", "Joyce", "Sarah", "Ajlin",
                         "Enes", "Leon", "Boran", "Joshua");


document.getElementById('tot1').innerHTML = getStudent(students);
document.getElementById('tot2').innerHTML = getStudent(students);
document.getElementById('tot3').innerHTML = getStudent(students);


getStudent(), script. splice , .

edit2: -1 .length. 1 Math.random(), .

http://jsfiddle.net/northkildonan/38rf42f7/1/

edit: script.

+5

:

 students = new Array("Paul", "Jan", "Fabian D.", "Fabian K.", "Lennard",                   "Robin", "Angelique", "Joyce", "Sarah", "Ajlin",
"Enes", "Leon", "Boran", "Joshua")    


var arr = []
while(arr.length < 3){
  var randomnumber=Math.ceil(Math.random()*students.length-1)
  var found=false;
  for(var i=0;i<arr.length;i++){
    if(arr[i]==randomnumber){found=true;break}
  }
  if(!found)arr[arr.length]=randomnumber;
}
console.log(arr.valueOf());

tot1 = students[arr[0]];

tot2 = students[arr[1]];

tot3 = students[arr[2]];

document.getElementById('tot1').innerHTML = tot1;
document.getElementById('tot2').innerHTML = tot2;
document.getElementById('tot3').innerHTML = tot3;

, 1, 0.

http://jsfiddle.net/t4mtpm50/6/

+3

- , . ( fooobar.com/questions/24557/....)

function shuffle(array) {
    var i, temp, j;
    for (i = array.length; i; i--) {
        j = Math.floor(Math.random() * i);
        temp = array[i - 1];
        array[i - 1] = array[j];
        array[j] = temp;
    }
}
students = ["Paul", "Jan", "Fabian D.", "Fabian K.", "Lennard", 
                            "Robin", "Angelique", "Joyce", "Sarah", "Ajlin",
                            "Enes", "Leon", "Boran", "Joshua"];
shuffle(students);
document.getElementById('tot1').innerHTML = students[0];
document.getElementById('tot2').innerHTML = students[1];
document.getElementById('tot3').innerHTML = students[2];

http://jsfiddle.net/4o897kwa/1

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