How to sort a HashMap, values are integers. I want to sort from highest to lowest

Question

So, I need to sort a "scores" hashmap. the hashmap layout is HashMap<Player, Integer(which is the score i need to sort>

if you're asking why? its because i need to make a leaderboard.

here is my code:

public static Player[] sortPlayersByElo() {
        Map<String, Object> map = RankingConfig.get().getConfigurationSection("data").getValues(false);
        Map<Player, Integer> eloMap = new HashMap<>(); // Here is the map i need to sort.
        for (String s : map.keySet()) {
            Player player = Bukkit.getPlayer(s);
            eloMap.put(player, RankingConfig.get().getInt("data."+s+".elo"));
        }
        
        Player[] players = new Player[eloMap.size()];

        return players;
    }

Did you try this: https://www.google.com/search?q=java+sort+hashmap — dominicoder, Aug 08 '21 at 17:32
You need to explain what is is that you have tried to come to the conclusion that "nothing works". — dominicoder, Aug 08 '21 at 17:35
My question got answered already. Thanks for your help anyways. — Aly Mobarak, Aug 08 '21 at 17:54

score 4 · Accepted Answer · answered Aug 08 '21 at 17:33

You can use Comparator.comparingInt to sort in the correct order. Streams can be used to sort and collect the new Map to a LinkedHashMap to retain the new order.

Map<Player, Integer> result = eloMap.entrySet().stream()
    .sorted(Comparator.comparingInt(Map.Entry::getValue))
    .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue, 
         (a,b)->b, LinkedHashMap::new));

How to sort a HashMap, values are integers. I want to sort from highest to lowest

1 Answers1