What's the simplest way to convert a String Array to an int Array using Java 8? [closed]

Answer 1

For example:

static int[] parseIntArray(String[] arr) {
    return Stream.of(arr).mapToInt(Integer::parseInt).toArray();
}

So take a Stream of the String[]. Use mapToInt to call Integer.parseInt for each element and convert to an int. Then simply call toArray on the resultant IntStream to return the array.

Answer 2

You may skip creating the token String[] array:

Pattern.compile(" ")
       .splitAsStream(input.nextLine()).mapToInt(Integer::parseInt).toArray();

The result of Pattern.compile(" ") may be remembered and reused, of course.

Answer 3

You could, also, obtain the array directly from a split:

String input; //Obtained somewhere
...
int[] result = Arrays.stream(input.split(" "))
        .mapToInt(Integer::valueOf)
        .toArray();

Here, Arrays has some nice methods to obtain the stream from an array, so you can split it directly in the call. After that, call mapToInt with Integer::valueOf to obtain the IntStream and toArray for your desired int array.