How to sort the string on the basis of the frequency which is a part of a string?

Question

I have a single string variable 'v1' of the form(every line is split using "\r\n"):

a, 2.0, 2.0, 3.0
b, 1.0, 3.0, 6.8
c, 4.0, 2.8, 5.4

The output should be a single string variable 'out1' of the form:

b, 1.0, 3.0, 6.8
c, 4.0, 2.8, 5.4
a, 2.0, 2.0, 3.0

I am supposed to sort the above input on the basis of the part of the string written after the last comma of every line(eg.: 6.8, 5.4 and 3.0 in the above case). This is to be done in java.

How to implement it(no need to worry about efficiency)?

Answer 1

Maybe you could do:

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;

public class Sample {

    public static void main(String[] args) {
        String v1 = "a, 2.0, 2.0, 3.0\r\nb, 1.0, 3.0, 6.8\r\nc, 4.0, 2.8, 5.4\r\n";
        List<String> list = new ArrayList<String>();
        for(String line: v1.split("\r\n")) {
            list.add(line);
        }
        Collections.sort(list, new Comparator<String>() {
            public int compare(String s1, String s2) {
                Float f1 = Float.parseFloat(s1.split(",")[3].trim());
                Float f2 = Float.parseFloat(s2.split(",")[3].trim());
                return f2.compareTo(f1);
            }
        });
        StringBuilder result = new StringBuilder();
        for(String line: list) {
            System.out.println(line);
            result.append(line+"\r\n");
        }
        System.out.println(result.toString());
    }
}