Get random item from JavaScript array [duplicate]

Get random item from JavaScript array [duplicate]

Getting a random value from a JavaScript array

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

How do I get random item from items?

Solution 1:

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

Solution 2:

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 = jQuery.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 đź™‚

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

Solution 3:

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];
``````

Solution 4:

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

Solution 5:

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])
``````

Solution 6:

Here’s yet another way:

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