What is the math object for doing a random choice between 5 numbers? (JAVASCRIPT)

Answer 1

var myArr = [ 42, 3, 27, 5, 12 ];
var index = Math.round(4*Math.random());
var selected = myArr[index];

Answer 2

More generally, use:

Math.round((myArr.length-1)*Math.random());

- Math.random() return a float in [0;1[
- Math.round() round this to the nearest integer, so to have an integer [0;n] range, you need to multiply by length-1

Answer 3

You can also use:

Math.floor(myArr.length*Math.random());

... as Math.floor() round to nearest lowest integer ;)

Answer 4

Yes:

https://developer.mozilla.org/pt-PT/docs/Web/JavaScript/Reference/Global_Objects/Math/round
https://developer.mozilla.org/uk/docs/Web/JavaScript/Reference/Global_Objects/Math/floor
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/ceil

Answer 5

Math.round(x), not Math.round10(x)... takes only once parameter ^^

Answer 6

So you have used Math.round and Math.random

Why did you use 4*Math.random , to enlarge the range of operation of random function? (I'm just guessing...)

Answer 7

Perfect explaination! Thank you.

Answer 8

The difference between Math.floor and Math.round is just the word "lowest" ?

Answer 9

Ah, ok. But is it necessary to specify Math.round10(55.46, 1) or it just works with Math.round10(55.46)