How can I generate a random number within a range

Question

Basically I pick a random number between 0-24:

Math.floor(Math.random() * myArray.length); // myArray contains 25 items

Lets say it comes out to be 8. Now I want to get another number in the same range 0-24 but this time, I do not want an 8. The next time, I might roll a 15. Now I want to roll again but I don't want an 8 or 15. The way I am handling this now is by using do while loops and if the number comes out the same, I just reroll.

This is a small portion of my homework and I, in fact, have it working to meet all the requirements so I guess you could say this is for my own personal benefit so I can write this properly and not end up on "the daily wtf".

Answer 1

Here is a tested and simple solution:

var array= [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24];
var random_value; 
var index;
var shuffled_array = new Array(24);

for (var i = 0; i < 24; i++) { 
random_value = array[Math.floor(Math.random()*array.length)]; //Returns a value between 1 and 24
index = array.indexOf(random_card); //Gets the index of the choosen random value
array.splice(index, 1); //Go to index of that array and remove it
shuffled_array [i] = random_value; //Put that value in a new array

window.alert("array: "+array+"\n"+"random_value: "+random_value+"\n"+"shuffled_array: "+shuffled_array);
}

In other solutions i believe they forgot to search for the index.

Answer 2

I'm sure there are a few ways to do this, but you could put all the numbers into something like a stack, jumble it all up and then pop off of it to get your random numbers. Or, randomly seek into it every time and remove it from the stack.