How do I convert a java ArrayList to the equivalent double[]

Question

Possible Duplicate:
How to cast from List<Double> to double[] in Java?

So far the only method I can get working is to loop through the entire array. I was hoping for something along the lines of:

ArrayList<Double> myArrayList = ... // initiaize
double[] myArray = ... // magic line here

Answer 1

Use Google Guava : Doubles.toArray

myArray = Doubles.toArray(myArrayList);

Answer 2

You cannot go from ArrayList<Double> to double[] with a single call using the sandard Java API. However, take a look at the ArrayUtils class available from Apache's site.

On a side note, if you need to change your ArrayList into a primitive array, perhaps your problem is somewhere else. If you explain further exactly what you are trying to achieve, we could provide you better help than a simple API hack.