Map Demo

Simulate the action to put multiple rounds of test results into a map

import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.Map;

public class MapDemo {

    public static void main(String[] args) {

        Map> map = new LinkedHashMap<>();

        String key;
        int value;
        for (int i = 1; i <= 9; i ++) {

            if (i <= 3) {
                key = "First";
            } else if (i <= 6) {
                key = "Second";
            } else {
                key = "Third";
            }
            value = i;

            if (!map.containsKey(key)) {
                ArrayList arr = new ArrayList<>();
                arr.add(value);
                map.put(key, arr);
            } else {
                map.get(key).add(value);
            }

        }

        System.out.println(map);
    }

}

{First=[1, 2, 3], Second=[4, 5, 6], Third=[7, 8, 9]}