How to convert int[] into List<Integer> in Java?
Streams
- In Java 8+ you can make a stream of your
intarray. Call eitherArrays.streamorIntStream.of. - Call
IntStream#boxedto use boxing conversion fromintprimitive toIntegerobjects. - Collect into a list using
Stream.collect( Collectors.toList() ). Or more simply in Java 16+, callStream#toList().
Example:
int[] ints = {1,2,3};List<Integer> list = Arrays.stream(ints).boxed().collect(Collectors.toList());In Java 16 and later:
List<Integer> list = Arrays.stream(ints).boxed().toList();
There is no shortcut for converting from int[] to List<Integer> as Arrays.asList does not deal with boxing and will just create a List<int[]> which is not what you want. You have to make a utility method.
int[] ints = {1, 2, 3};List<Integer> intList = new ArrayList<Integer>(ints.length);for (int i : ints){ intList.add(i);}