Question

I have an arrayList with 30 elements. I’d like to create many sublists of 15 elements from this list. What’s the efficient way of doing so?

Right now I clone the ArrayList and use remove(random) to do it, but I am sure this is too clumsy. What should I do instead?
Does Java have a “sample” function like in R?

Clarification: by sampling with no replacement I mean take at random 15 unique elements from the 30 available in the original list. Moreover I want to be able to do this repeatedly.

Answer 1

Use the Collections#shuffle method to shuffle your original list, and return a list with the first 15 elements.