Sorting multidimensional array with index and value

Question

I have an multidimensional array consists of key and value. Based on sort value i have to arrange key values For Eg:

Multidimensional array:
key Value
1    5
4    2
3    4
8    1
6    2

I have to arrange keys based ascending order of values 
Answer:
8 1
4 2
6 2
3 4
1 5

@JeevanRoydsouza next time put relevant tags only. I removed other tags — Ruchira Gayan Ranaweera, Dec 12 '13 at 09:19
This link could help as well. http://stackoverflow.com/questions/13852725/java-map-sort-by-value — Rufi, Dec 12 '13 at 09:33
@Vladimir Tikhomirov Thank You for the link.Its working fine. — Jeevan Roy dsouza, Dec 12 '13 at 09:58

score 1 · Answer 1 · answered Dec 12 '13 at 09:19

Use a TreeMap in which you put values mapped to keys (so you reverse their meanings for your case).

Just add the elements in the TreeMap and you will have them sorted.

This will work if you don't have multiple keys mapped to the same value (key/value in this last sentence is used in your meaning, not in the usual Map meaning).

score 1 · Answer 2 · answered Dec 12 '13 at 09:24

do like this

Integer[][] array ={{1,5},{4,2},{3,4},{8,1},{6,2}};
Arrays.sort(array, new Comparator<Integer[]>() {
    @Override
    public int compare(Integer[] o1, Integer[] o2) {
    return o1[1].compareTo(o2[1]);
    }
});
System.out.println(Arrays.deepToString(array));

Output

[[8, 1], [4, 2], [6, 2], [3, 4], [1, 5]]

score 1 · Accepted Answer · edited Dec 12 '13 at 12:07

Try this one:

static class ValueComparator implements Comparator<String> {

    Map<String, Integer> base;

    ValueComparator(Map<String, Integer> base) {
        this.base = base;
    }

    @Override
    public int compare(String a, String b) {
        Integer x = base.get(a);
        Integer y = base.get(b);
        if (x.equals(y)) {
            return a.compareTo(b);
        }
        return x.compareTo(y);
    }
}


HashMap<String, Integer> map = new HashMap<String, Integer>();
ValueComparator vc = new ValueComparator(map);
TreeMap<String, Integer> sorted = new TreeMap<String, Integer>(vc);

map.put("z",30);
map.put("e",10);
map.put("b",20);
map.put("c",20);

sorted.putAll(map);

for (String key : sorted.keySet()) {
    System.out.println(key + " : " + sorted.get(key)); 
}

score 0 · Answer 4 · answered Dec 12 '13 at 12:09

0

You have bad collection. You should have used map.

answered Dec 12 '13 at 12:09

Marcin Szymczak

11,199
5
55
63

Any other way is there for doing other then hash map? – Jeevan Roy dsouza Dec 12 '13 at 12:23
Well, you can do this with every collection (or combination of them) but for key/value pairs maps are natural choice. You do not have to reinvent the wheel. – Marcin Szymczak Dec 12 '13 at 12:32
So you are telling me to use my own logic instead of using hashmap? – Jeevan Roy dsouza Dec 12 '13 at 12:46

Sorting multidimensional array with index and value

4 Answers4