Shuffling an array

I would like to shuffle this array:

private var  lettersL1:Array = [a,a,f,f,f,g,h,i,i,n,n,n,o,o,o,o,s,s,t,t,t];

          for (var i: Number  =0; i < lettersL1.length; i++)

                {

                    trace (lettersL1[i]);                  

                }

I tried this:

lettersL1.push[i];

                    var shuffledArray:Array = new Array [];

                    while (lettersL1.length > 0)

                        {

                            var r:int = Math.floor(Math.random()*lettersL1.length);

                            shuffledArray.push(lettersL1[i]);

                            lettersL1[i].slice[r,1];

                        }

                trace(shuffledArray[r]);

Where did I go wrong. Is there a better way?

Thanks

Charine