How can I get a random integer using the random() function in p5.js?

For example this code:

var num = random(0, 1);
console.log(num);

outputs decimal numbers to the console.

How can I get a random integer?

How can I get a random integer using the random() function in p5.js?

For example this code:

var num = random(0, 1);
console.log(num);

outputs decimal numbers to the console.

How can I get a random integer?

• javascript
• html
• p5.js

4 Answers 4

If you want integer numbers from 0 to 10, both inclusive:

function setup() {
  var num = int(random(0, 11));
  print(num);
}

<script src="https://cdnjs.cloudflare./ajax/libs/p5.js/1.6.0/p5.js"></script>

Explanation:

random(0, 11) returns numbers from 0 to 10.999999999..., but never 11.

int() converts those decimal numbers to integer

int(random(0, 11)) returns numbers between 0 and 10, both inclusives.

Why not use simple JavaScript as demonstrated here?

Excluding max value:

function getRndInteger(min, max) {
    return Math.floor(random(min, max)) + min;
}

Including limits:

function getRndInteger(min, max) {
    return Math.floor(random(min + 1, max)) + min;
}

The p5.js random() function will always return a floating-point number (aka. decimal number). If you want an integer you can use JavaScript Math.round() to round the number to the nearest whole number.

To get a zero or one. The best method is:

Math.round(random());

You can also use int() to have JavaScript convert the number to an integer but it has a major problem where it simply ignores the decimals, in effect rounding the number down.
This is a problem with p5.js random() because random() will return a random number from the minimum up to but not including the maximum. The maximum of random(0, 1) is 0.99999... which int() always converts to 0;

This means for example:

• random() will never return 1. Meading int(random()) always returns 0
• random(0, 15) will never return 15. Meaning int(random(15)) would never return 15

So, how I would do this, is assign a floored random number to a variable.

E.G.

var r = Math.floor(random(0,11));
console.log(r);

-Valkyrie