JavaScript array_rand

Return key/keys for random entry/entries in the array

function array_rand ( input, num_req ) {
    // Return key/keys for random entry/entries in the array  
    // 
    // version: 909.322
    // discuss at: http://phpjs.org/functions/array_rand    // +   original by: Waldo Malqui Silva
    // *     example 1: array_rand( ['Kevin'], 1 );
    // *     returns 1: 0
    var indexes = [];
    var ticks = num_req || 1;    var checkDuplicate = function ( input, value ) {
        var exist = false, index = 0;
        while ( index < input.length ) {
            if ( input [ index ] === value ) {
                exist = true;                break;
            }
            index++;
        }
        return exist;    };
 
    if ( input instanceof Array && ticks <= input.length ) {
        while ( true ) {
            var rand = Math.floor( ( Math.random( ) * input.length ) );            if ( indexes.length === ticks ) { break; }
            if ( !checkDuplicate( indexes, rand ) ) { indexes.push( rand ); }
        }
    } else {
        indexes = null;    }
 
    return ( ( ticks == 1 ) ? indexes.join( ) : indexes );
}

external links: original PHP docs | raw js source

Examples

Running

1	array_rand( ['Kevin'], 1 );

Should return

Dependencies

No dependencies, you can use this function standalone.

Open syntax issues

php.js uses JsLint to help us keep our code consistent and prevent some common bugs.

Eventually we want all code to pass or at least take into consideration most fixes suggested by JsLint, following this JsLint configuration we’ve decided on.

Authors

Thanks to the following developers, you get to have array_rand goodness in JavaScript.

Waldo Malqui Silva ( original )

Comments

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Use:

[CODE]
your_stuff('here');
[/CODE]

for proper code formatting
By submitting code here you are allowing us to use it in php.js hence dual licensing it under the MIT and GPL licenses

pwoul
10 May '09

thanks a lot, that's working now :)
(here's the code if someone needs it)

var result = "";
alea = array_rand(["a","b","c","d","e","f","g","h"], 8);
for(var i in alea)
        {
        var kikoo = alea[i];        result = result + tableau[kikoo];
        }

Brett Zamir
9 May '09

@pwoul, You are referencing an array/object called "tableau" instead of the one you randomized, "alea". Change it to "alea" (if that's what you want), and the number will vary... best wishes, Brett

pwoul
9 May '09

Hi, first i'd like to thank you for this very nice function.
But (there's always one :D) i have a problem using it :

var result = "";
var alea = array_rand(["a","b","c","d","e","f","g","h"], 8);
for(var i in alea)
        {
        result = result + tableau[i];        }

This code always returns the string "abcdefgh", the order of the characters isn't random :/

Thanks for your help :)

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