// chops a list into non-view sublists of length L static <T> List<List<T>> chopped(List<T> list, final int L) { List<List<T>> parts = new ArrayList<List<T>>(); final int N = list.size(); for (int i = 0; i < N; i += L) { parts.add(new ArrayList<T>( list.subList(i, Math.min(N, i + L))) ); } return parts; }
Usage:
List<Integer> numbers = Collections.unmodifiableList( Arrays.asList(5,3,1,2,9,5,0,7) ); List<List<Integer>> parts = chopped(numbers, 3); System.out.println(parts); // prints "[[5, 3, 1], [2, 9, 5], [0, 7]]" parts.get(0).add(-1); System.out.println(parts); // prints "[[5, 3, 1, -1], [2, 9, 5], [0, 7]]" System.out.println(numbers); // prints "[5, 3, 1, 2, 9, 5, 0, 7]" (unmodified!)
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