javascript random item in array?

Question

So I have an array of strings: ["a", "b", "c", "d"], but I want array[4] to be a random string each time it is used, so:

array[0] returns "a",
array[1] returns "b",

array[4] returns something random, like "x",
array[4] returns something random the second time as well, like "y",

There is a function random(), but if I set array[4] equal to random() it will hold on to that random value, but it needs to stay random every time it is called.

This seems like something better suited for javascript object/class using getters and setters — OtotheA
– OtotheA, Commented Sep 26, 2014 at 14:03
No I want to call array[4] not random, I know it's a bit vague — GottaLovePizzas
– GottaLovePizzas, Commented Sep 26, 2014 at 14:04
+1 to this question that made me learn something I could not think was possible! — FrancescoMM
– FrancescoMM, Commented Sep 26, 2014 at 14:27

Dagg Nabbit · Accepted Answer · 2014-09-26 14:06:53Z

7

Use Object.defineProperty.

var a = ["a", "b", "c", "d"];
Object.defineProperty(a, 4, { get: Math.random });

console.log(a[4]); // some random number
console.log(a[4]); // another random number

answered Sep 26, 2014 at 14:06

Dagg Nabbit

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3 Comments

FrancescoMM Over a year ago

nice! Didn't know that!

Dagg Nabbit Over a year ago

@FrancescoMM the nice thing about Object.defineProperty is it doesn't require any special syntax and it works after the object is instantiated. If you don't mind special-purpose syntax and can get away with setting up the accessor during instantiation, your solution works too (+1 to you).

FrancescoMM Over a year ago

..but mine is not even an array.. :(

FrancescoMM · Accepted Answer · 2014-09-26 14:11:59Z

1

var array = { get 4() {return getRandomInt(1,10);} }

alert(array[4]);
alert(array[4]);
alert(array[4]);



function getRandomInt(min, max) {
  return Math.floor(Math.random() * (max - min)) + min;
}

answered Sep 26, 2014 at 14:11

FrancescoMM

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Comments

yuanzm · Accepted Answer · 2014-09-26 14:08:43Z

-1

    function random() {
        character = String.fromCharCode(Math.floor( Math.random() * 26) + "a".charCodeAt(0));
        return character;
    }

answered Sep 26, 2014 at 14:08

yuanzm

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Comments

OtotheA · Accepted Answer · 2014-09-26 14:10:13Z

-1

Here's how you could accomplish similar functionality

arrayManager = {
    array: ["a", "b", "c", "d"]
    set: function(i, v) {
        this.array[i] = v;
    }
    get: function(i) {
        if (i == 4) return random();
        else return this.array[i];
    }
};

var random = arrayManager.get(4);

answered Sep 26, 2014 at 14:10

OtotheA

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