Get random item from JavaScript array [duplicate]

If you really must use jQuery to solve this problem:

(function($) {
    $.rand = function(arg) {
        if ($.isArray(arg)) {
            return arg[$.rand(arg.length)];
        } else if (typeof arg === "number") {
            return Math.floor(Math.random() * arg);
        } else {
            return 4;  // chosen by fair dice roll
        }
    };
})(jQuery);

var items = [523, 3452, 334, 31, ..., 5346];
var item = $.rand(items);

This plugin will return a random element if given an array, or a value from [0 .. n) given a number, or given anything else, a guaranteed random value!

For extra fun, the array return is generated by calling the function recursively based on the array's length :)

Working demo at http://jsfiddle.net/2eyQX/

Use underscore (or loDash :)):

var randomArray = [
   '#cc0000','#00cc00', '#0000cc'
];

// use _.sample
var randomElement = _.sample(randomArray);

// manually use _.random
var randomElement = randomArray[_.random(randomArray.length-1)];

Or to shuffle an entire array:

// use underscore's shuffle function
var firstRandomElement = _.shuffle(randomArray)[0];

var random = items[Math.floor(Math.random()*items.length)]

var rndval=items[Math.floor(Math.random()*items.length)];

jQuery is JavaScript! It's just a JavaScript framework. So to find a random item, just use plain old JavaScript, for example,

var randomItem = items[Math.floor(Math.random()*items.length)]

var items = Array(523,3452,334,31,...5346);

function rand(min, max) {
  var offset = min;
  var range = (max - min) + 1;

  var randomNumber = Math.floor( Math.random() * range) + offset;
  return randomNumber;
}


randomNumber = rand(0, items.length - 1);

randomItem = items[randomNumber];

credit:

http://www.earn-web-cash.com/2008/02/24/random-number-function/

Here's yet another way:

function rand(items){
    return items[~~(Math.random() * items.length)];
}

// 1. Random shuffle items
items.sort(function() {return 0.5 - Math.random()})

// 2. Get first item
var item = items[1]

Shorter:

var item = items.sort(function() {return 0.5 - Math.random()})[1];

1. solution: define Array prototype

Array.prototype.random = function () {
  return this[Math.floor((Math.random()*this.length))];
}

that will work on inline arrays

[2,3,5].random()

and of course predefined arrays

list = [2,3,5]
list.random()

2. solution: define custom function that accepts list and returns element

    get_random = function (list) {
      return list[Math.floor((Math.random()*list.length))];
    } 

    get_random([2,3,5])

If you are using node.js, you can use unique-random-array. It simply picks something random from an array.

An alternate way would be to add a method to the Array prototype:

 Array.prototype.random = function (length) {
       return this[Math.floor((Math.random()*length))];
 }

 var teams = ['patriots', 'colts', 'jets', 'texans', 'ravens', 'broncos']
 var chosen_team = teams.random(teams.length)
 alert(chosen_team)

Array.prototype.random = function () {
  return this[Math.random() * this.length | 0];
};

Array.prototype.pick = function (i) {
  return this.splice(i >= 0 ? i : Math.random() * this.length | 0, 1)[0];
};

Array.prototype.shuffle = function () {
  for (var i = this.length; i > 0; --i)
    this.push(this.splice(Math.random() * i | 0, 1)[0]);
  return this;
};