Question

I am facing a problem in sorting. The format of data is:

b4 S0_c5 t 0.426544 
b6 S1_c5 t 1.51049 
b13 S0_c5 t 0.594502 
b13 S1_c5 t 0.537496 
b15 S1_c5 t 0.884126   
b18 S0_c5 t 0.500933 
b19 S1_c5 t 0.628472 
b22 S0_c5 t 0.437718 

and required result is:

S0_c5 b13 0.594502 b18 0.500933 b22 0.437718 b4 0.426544 
S1_c5 b6 1.51049 b15 0.884126 b19 0.628472 b13 0.537496 

the value is also in descending order. Thanks in advance.

Answer 1

Put the data in a TreeList<String, List<String>> (because it’s sorted) where the second word from a sequence is the key, and the value a list of strings, then sort each list you obtain this way:

    Map<String, List<String[]>> map = new TreeMap<String, List<String[]>>();
    for (String s : strings) {
        String[] tokens = s.split(" ");
        List<String[]> values = map.get(tokens[1]);
        if (values == null) {
            values = new ArrayList<String[]>();
            map.put(tokens[1], values);
        }
        values.add(new String[]{tokens[0],  tokens[3]});
    }

    for (String key : map.keySet()) {
        List<String[]> list = map.get(key);
        Collections.sort(list, new Comparator<String[]>() {

            @Override
            public int compare(String[] o1, String[] o2) {
                return o1[1].compareTo(o2[1]) * -1;
            }

        });

        System.out.print(key + " ");
        for (String[] s : list) {
            System.out.print(s[0] + " " + s[1]);
        }
        System.out.println();
    }

Update:
E.g. to read from a file:

    BufferedReader br;
    try {
        br = new BufferedReader(new FileReader("d:/temp/r.res"));

        Map<String, List<String[]>> map = new TreeMap<String, List<String[]>>();
        while (br.ready()) {
            String s = br.readLine();
            if (!s.trim().isEmpty()) {
                String[] tokens = s.split(" ");
                List<String[]> values = map.get(tokens[1]);
                if (values == null) {
                    values = new ArrayList<String[]>();
                    map.put(tokens[1], values);
                }
                values.add(new String[]{tokens[0],  tokens[3]});
            }
        }
    } finally {
        br.close();
    }