Simplest way to prevent math.random form selecting the same number twice (AS3) - actionscript-3

Question

I have a random number variable defined as below
var rannum:Number = Math.floor(Math.random()*50+1);
Then I have a trigger that calls for a new random number everytime a button is clicked
ranbtn.addEventListener(MouseEvent.CLICK, reran);
function reran (event:MouseEvent):void
{
rannum = Math.floor(Math.random()*50+1);
}
I would like to prevent the same random number from being selected until all the numbers have been selected and then possibly start over?
I found a few threads like this one but none of them were specifically what I needed

Answer 1

You need to create an array of the possible values and each time you retrieve a random index from the array to use one of the values, you remove it from the array.Here you have an easy example with javascript.
var uniqueRandoms = [];
var numRandoms = 50;
function makeUniqueRandom() {
// refill the array if needed
if (!uniqueRandoms.length) {
for (var i = 0; i < numRandoms; i++) {
uniqueRandoms.push(i);
}
}
var index = Math.floor(Math.random() * uniqueRandoms.length);
var val = uniqueRandoms[index];
// now remove that value from the array
uniqueRandoms.splice(index, 1);
return val;
}
I've found another option, You can declare an array of Integers:[1,2,3,4...50] and sort them randomly.
var sorted:Array = [];
for(var i:int = 0; i < 50; i++){
sorted.push(i);
}
//I'm making a copy of sorted in unsorted
var unsorted:Array = sorted.slice();
//Randomly sort
while(sorted.join() == unsorted.join()){
unsorted.sort(function (a:int, b:int):int { return Math.random() > .5 ? -1 : 1; });
}

Answer 2

If you get a selected num, you can add one until it is not selected.

Answer 3

Create a list of integers from 1 to 50.
Pick a random integer from the list and remove it.
When there are no more integers left (after 50 picks), repeat step 1.
Code:
function createRangeOfIntegers(from:int, to:int):Vector.<int> {
if (from >= to) throw new ArgumentError("Invalid arguments");
var integers:Vector.<int> = new <int>[];
for (var i:int = from; i <= to; i++) {
integers.push(i);
}
return integers;
}
function getRandomInteger(integers:Vector.<int>):int {
var index:int = Math.random() * integers.length;
var integer:int = integers.splice(index, 1)[0];
return integer;
}
Example:
// create all the possible integers
var integers:Vector.<int> = createRangeOfIntegers(1, 50);
// select a random integer
var random:int = getRandomInteger(integers);
// When you've selected all integers you can start over
if (integers.length == 0)
integers = createRangeOfIntegers(1, 50);