diff --git a/README.md b/README.md index 4b27590..35a0ac2 100644 --- a/README.md +++ b/README.md @@ -2,3 +2,69 @@ knuth-shuffle ============= The Fisher-Yates (aka Knuth) shuffle for Browser and Node.js + +The Fisher-Yates (Knuth) Shuffle +=== + +As Microsoft learned the hard way (see article below), `function random() { return 0.5 - Math.random() }` turns out to be no-so-random at all. + +The fisher-yates shuffle is an algorithm so simple that not even +[IEEE floating point math](http://blogs.adobe.com/bparadie/2011/11/22/0-2-0-1-0-30000000000000004/) +can screw it up! + +I put this on npm as `knuth-shuffle` because `fisher-yates-shuffle` +was just too long of a name and shuffle was already taken. + +Browser Example +=== + +```html + +``` + +```javascript +(function () { + 'use strict'; + + var a = [2,11,37,42] + , b + ; + + // The shuffle modifies the original array + // calling a.slice(0) creates a copy, which is assigned to b + b = window.knuthShuffle(a.slice(0)); + console.log(); +}); +``` + +Node Example +=== + +```bash +npm install -S knuth-shuffle +``` + +```javascript +(function () { + 'use strict'; + + var shuffle = require('knuth-shuffle').knuthShuffle + , a = [2,11,37,42] + , b + ; + + // The shuffle modifies the original array + // calling a.slice(0) creates a copy, which is assigned to b + b = shuffle(a.slice(0)); + console.log(); +}); +``` + +See Also +=== + + * [Mike Bostock's Fisher–Yates Shuffle Visualization](http://bost.ocks.org/mike/shuffle/) + * [How to randomize/shuffle a JavaScript array](http://stackoverflow.com/questions/2450954/how-to-randomize-shuffle-a-javascript-array) + * [Fisher-Yates Shuffle on Wikipedia](http://en.wikipedia.org/wiki/Fisher%E2%80%93Yates_shuffle) + * [Doing the Microsoft Shuffle: Algorithm Fail in Browser Ballot](http://www.robweir.com/blog/2010/02/microsoft-random-browser-ballot.html) + * [knuth-shuffle on NPM](https://npmjs.org/package/citare-scriptum)