benhowdle89 - 1 year ago 51

Javascript Question

I need to generate a set of unique (no duplicate) integers, and between 0 and a given number.

That is:

`var limit = 10;`

var amount = 3;

How can I use Javascript to generate 3 unique numbers between 1 and 10?

Answer Source

Use the basic `Math`

methods:

`Math.random()`

returns a random number between 0 and 1 (including 0, excluding 1).- Multiply this number by the highest desired number (eg 10)
Round this number

`Math.round(Math.random()*10) + 1`

Example:

```
//Example, including customisable intervals [lower_bound, upper_bound)
var limit = 10,
amount = 3,
lower_bound = 1,
upper_bound = 10,
unique_random_numbers = [];
if (amount > limit) limit = amount; //Infinite loop if you want more unique
//Natural numbers than existemt in a
// given range
while (unique_random_numbers.length < limit) {
var random_number = Math.round(Math.random()*(upper_bound - lower_bound) + lower_bound);
if (unique_random_numbers.indexOf(random_number) == -1) {
// Yay! new random number
unique_random_numbers.push( random_number );
}
}
// unique_random_numbers is an array containing 3 unique numbers in the given range
```