how to auto generate the key in linkhashmap in java

Question

i make a linkedhashmap like this in java using netbean

LinkedHashMap map = new LinkedHashMap();

 map.put(0, "one");
 map.put(1, "two");
 map.put(2, "three");

in the above code the key(0,1,2), i want that it auto generate. I try different online solution but doesn't work.

What's the point of using a `Map` when your keys are just indicies 0 ... size - 1? — d.j.brown, Apr 05 '18 at 11:14
why don't you use list instead of map.. you can assume indexes as key.. — DhaRmvEEr siNgh, Apr 05 '18 at 11:29
Actually this is the case, i do hope know you will understand.. stackoverflow.com/questions/49677006 — naeem, Apr 05 '18 at 16:31

score 1 · Answer 1 · answered Apr 05 '18 at 11:12

1

You can use map.size():

map.put(map.size(), "one"); // map.size() returns 0
map.put(map.size(), "two"); // map.size() returns 1
map.put(map.size(), "three"); // map.size() returns 2
...

answered Apr 05 '18 at 11:12

Eran

387,369
54
702
768

score 0 · Answer 2 · answered Apr 05 '18 at 11:47

public class Main {
    public static void main(String[] args) {
        Map<Integer, String> map = new LinkedHashMap<>();
        map.put(KeyGenerator.getNextKey(), "One");
        map.put(KeyGenerator.getNextKey(), "Two");
        map.put(KeyGenerator.getNextKey(), "Three");
        map.forEach((key, value) -> System.out.println("Key = " + key + ", value = " + value));
    }

    static class KeyGenerator {
        private static AtomicInteger key = new AtomicInteger(0);
        public static int getNextKey() {
            return key.getAndAdd(1);
        }
    }
}

score 0 · Accepted Answer · answered Apr 05 '18 at 12:38

0

public class Test {

    static int i = 0;

    public static void main(String[] args) {

        Map<Integer, String> map = new LinkedHashMap<>();
        map.put(getNext(), "One");
        map.put(getNext(), "Two");
        map.put(getNext(), "Three");
        map.forEach((key, value) -> System.out.println("Key = " + key + ", value = " + value));
    }

    static int getNext() {
        i = i+1;
        return i;
    }
}

answered Apr 05 '18 at 12:38

Narendra Kekane

86
4

thanks it helps a lot.. Thanks Narendra for your ans it help, i have one more problem i do hope you will find it interested. stackoverflow.com/questions/49677006/… – naeem Apr 05 '18 at 16:28

how to auto generate the key in linkhashmap in java

3 Answers3