Sort a hash map that contains double and string values

Question

I have been given a text file with for a winter Olympic event. It contains team, name of competitor and score.

FRAMae Berenice MEITE         455.455
CHNKexin ZHANG                454.584
UKRNatalia POPOVA             453.443
GERNathalie WEINZIERL         452.162
RUSEvgeny PLYUSHCHENKO        191.399
CANPatrick CHAN               189.718
CHNHan YAN                    185.527
CHNCheng & Hao                271.018
ITAStefania & Ondrej          270.317
USAMarissa & Simon            264.256
GERMaylin & Daniel            260.825
FRAFlorent AMODIO             179.936
GERPeter LIEBERS              179.615
ect....

The only digit that maters is the last digit in the number. for each team, I need to sum their total points together and display the top 5 teams.

Code so far:

public class project2 {

public static void main(String[] args) throws IOException {
    // TODO Auto-generated method stub

    String[] array = new String[41];
    String[] info = new String [41];
    String[] stats = new String[41];    
    String[] team = new String[41];

            //.txt file location
            FileInput fileIn = new FileInput(); 
            fileIn.openFile("C:\\Users\\O\\Desktop\\turn in\\team.txt");
            //txt file to array
            int i=0;
            String line = fileIn.readLine();
            array[i] = line; i++;
            while (line != null) { 

                line = fileIn.readLine();
                array[i] = line; i++;
            }

            System.out.println(array[1]);



            //Splitting up team/competitor name/score

            for (int j =0; j< 40; j++){
                team[j] = array[j].substring (0, 3).trim ();
                info[j] = array[j].substring (3, 30).trim ();
                stats[j] = array[j].substring (36).trim ();
            }


            //random outputs ive been using fore testing.
            System.out.println(team[1]);
            System.out.println(info[1]);
            System.out.println(stats[1]);
            MyObject ob = new MyObject();
            ob.setText(info[0]);
            ob.setNumber(7, 23);
            ob.setNumber(3, 456);
            System.out.println("Text is " + ob.getText() + " and number 3 is " + ob.getNumber(7));

             for (int j =0; j< 40; j++){
                    team[j] = array[j].substring (0, 3).trim ();
                    info[j] = array[j].substring (3, 30).trim ();
                    stats[j] = array[j].substring (36).trim ();
                }


                //team and score in hashmap
                double[] statsDub = new double[40];
                for (int k =1; k < 40; k++){
                statsDub[k] = Double.parseDouble(stats[k]);
                }
                Map<String,Double> totalScore = new HashMap<>();
                for (int j =0; j< 40; j++){

                      Double tmp = totalScore.get (team[j]);
                        if (tmp != null)
                        {
                            totalScore.put(team[j], statsDub[j]+tmp);
                        }
                        else
                                totalScore.put(team[j], statsDub[j]);
                        }

                 // Get a set of the entries
                  Set set = totalScore.entrySet();
                  // Get an iterator
                  Iterator i1 = set.iterator();
                  // Display elements
                  while(i1.hasNext()) {
                     Map.Entry me = (Map.Entry)i1.next();
                     System.out.print(me.getKey() + ": ");
                     System.out.println(me.getValue());








    }}}



            //if (totalScore.containsKey("COUNTRYNAME"))
            //    totalScore.put("COUNTRYNAME", totalScore.get("COUNTRYNAME") + playerScore);
            //else
            //    totalScore.put("COUNTRYNAME",0);

I get this output:

GER: 17.0
USA: 27.0
ITA: 23.0
RUS: 37.0
CHN: 20.0
JPN: 24.0
FRA: 17.0
CAN: 32.0
UKR: 10.0
GBR: 8.0

How could I go about only having the top 5 teams displayed in descending order?

It would be a nice exercise for Java 8 streams (if you are allowed to use them). — PM 77-1, Oct 11 '14 at 19:35
You have the solution in this post (second response): http://stackoverflow.com/questions/8119366/sorting-hashmap-by-values — Mar Millán, Oct 11 '14 at 19:56

RealSkeptic · Accepted Answer · 2014-10-11T20:09:45.013

Create a class that implements Comparator, which can compare between two Map.Entry<String,Double> objects, based on the Double part.
Create a TreeSet<Map.Entry<String,Double>>, which is an implementation of an ordered set, with that comparator.
Now use the addAll method of the TreeSet to add the values from the set you got from totalScore.entrySet().
Iterate on the resulting set, keep an integer variable to count the number of iterations and stop at 5.

An alternative would be to copy the set to a List<Map.Entry<String,Double>> and then use Collections.sort to sort it. It still needs a comparator object!

Sort a hash map that contains double and string values

1 Answers1