## 問題 Problem 你想攪亂數組中的元素。 You want to shuffle the elements in an array. ## 方法 Solution JavaScript中的Array有一個`sort()`方法，接受一個自定義的排序函數。我們只需寫一個`shuffle()`函數就行。 The JavaScript Array?`sort()`?method accepts a custom sort function. We can write a?`shuffle()`?method to add some convenience. ~~~ Array::shuffle = -> @sort -> 0.5 - Math.random() [1..9].shuffle() # => [ 3, 1, 5, 6, 4, 8, 2, 9, 7 ] ~~~ ## 詳解 Discussion 更多關于這個混淆函數的工作原理，參看[StackOverflow上的討論](http://stackoverflow.com/questions/962802/is-it-correct-to-use-javascript-array-sort-method-for-shuffling)。 For more background on how this shuffle logic works, see this[discussion at StackOverflow](http://stackoverflow.com/questions/962802/is-it-correct-to-use-javascript-array-sort-method-for-shuffling). **注意：**?盡管這在常見的語言，比如說Ruby中很常見，但是在JavaScript中擴展原生對象往往被成是不好的實踐。(參看：?[Maintainable JavaScript: Don’t modify objects you don’t own](http://www.nczonline.net/blog/2010/03/02/maintainable-javascript-dont-modify-objects-you-down-own/);?[Extending built-in native objects. Evil or not?](http://perfectionkills.com/extending-built-in-native-objects-evil-or-not/))。 **Note:**?Although it’s quite common in languages like Ruby, extending native objects is often considered bad practice in JavaScript (see:?[Maintainable JavaScript: Don’t modify objects you don’t own](http://www.nczonline.net/blog/2010/03/02/maintainable-javascript-dont-modify-objects-you-down-own/);?[Extending built-in native objects. Evil or not?](http://perfectionkills.com/extending-built-in-native-objects-evil-or-not/)).