Stream Operation of Two dimensional array

Question

I am trying to find the best average score from below two dimensional array:

String[][] scores = { { "Amit", "70" }, { "Arthit", "60" }, { "Peter", "60" }, { "Arthit", "100" } };

The output is: 80 (Arthit's score (60+100)/2)

Till now I solved this problem with below approach, however I am looking for elegant solution with stream:

public static void main(String[] args) {
        String[][] scores = { { "Amit", "70" }, { "Arthit", "60" }, { "Peter", "60" }, { "Arthit", "100" } };

        int highestAvg = Integer.MIN_VALUE;
        Function<String[], Integer> function = new Function<String[], Integer>() {
            @Override
            public Integer apply(String[] t) {
                int sum = 0, count = 0;
                for (int i = 0; i < scores.length; i++) {
                    if (t[0].equals(scores[i][0])) {
                        count++;
                        sum += Integer.parseInt(scores[i][1]);
                    }
                }
                int avg = sum / count;
                return highestAvg < avg ? avg : highestAvg;
            }
        };
        System.out.println(Arrays.stream(scores).map(function).max((o1, o2) -> o1.compareTo(o2)).get());
    }

Would you please suggest, what's the better approach to handle two dimensional array using stream?

Note: I am not looking the exact solution, just looking your valuable suggestion.

Answer 1

You can make more use of built-in stream features, including averaging and grouping collectors:

Stream.of(scores)
        .collect(
                Collectors.groupingBy(a -> a[0], 
                Collectors.averagingInt(a -> Integer.parseInt(a[1]))))
        .entrySet()
        .stream()
        .max(Entry.comparingByValue())
        .ifPresent(bestScore -> {
                String message = String.format("Best score is %s, by %s", bestScore.getValue(), bestScore.getKey());
                System.out.println(message);
        });

Which prints Best score is 80.0, by Arthit