如何对由字符串数组组成的数组列表进行排序？

Question

I have a very problematic problem! I have an array list that looks like this:

 ArrayList<String[]> teamsToOrder = new ArrayList<String[]>();

In each string array that is added to the ArrayList looks like this:

 String[] arrayExample = {teamNumber,score};

 String[] array1 = {"340","100"};
 String[] array2 = {"7680","70"};
 String[] array3 = {"770","110"};
 ...........

What I want to be able to do is organize the arrays by score (best score to worst) like so:

 String[] array3 = {"770","110"};
 String[] array1 = {"340","100"};
 String[] array2 = {"7680","70"};
 ...........

How do I organize them and store them in the ArrayList? I am sorry to mention this, but my objective requires me to organize them in ArrayList form. I can't (i'm not allowed to) create a separate class for the data....

Answer 1

You can do it like this:

Collections.sort(teamsToOrder, new Comparator<String[]>() {
    public int compare(String[] lhs, String[] rhs) {
        // Parse the scores of the two items
        int leftScore = Integer.parseInt(lhs[1]);
        int rightScore = Integer.parseInt(rhs[1]);
        // Compare the two scores, and return the result
        return Integer.compare(leftScore, rightScore);
    }
});

Answer 2

This was my original post but I edited this to make it more simple:

Here is the way to sort the ArrayList<String[]> :

Collections.sort(teamsToOrder,new Comparator<String[]>() {
    public int compare(String[] s1, String[] s2) {

        return Integer.parseInt(s2[1]) - Integer.parseInt(s1[1]);
    }
});

---

That's it. So, as an example:

public static void main(String args[]) {

    ArrayList<String[]> teamsToOrder = new ArrayList<String[]>();
    String[] array1 = {"340","100"};
    String[] array2 = {"7680","70"};
    String[] array3 = {"770","110"};

    teamsToOrder.add(array1);teamsToOrder.add(array2);teamsToOrder.add(array3);

    Collections.sort(teamsToOrder,new Comparator<String[]>() {
        public int compare(String[] s1, String[] s2) {

            return Integer.parseInt(s2[1]) - Integer.parseInt(s1[1]);
        }
    });

    // display the new sorted ArrayList of String arrays:
    for (String[] s: teamsToOrder) {
        System.out.println(Arrays.toString(s));
    }
}

Output:

[770, 110]
[340, 100]
[7680, 70]

Answer 3

You should write a Comparator to compare the Strings the way you want to. Then sort your ArrayList using the implemented comparator. See: http://docs.oracle.com/javase/6/docs/api/java/util/Comparator.html

Answer 4

You can implement this by the following way. It is advisable to use List interface instead of ArrayList object.

public static void main(String[] args) {
        // TODO Auto-generated method stub
        List<String> entries = new ArrayList<String>();
        entries.add("0 - name1");
        entries.add("1000 - name2");
        entries.add("1004 - name4");
        entries.add("1002 - name3");
        entries.add("10000 - name5");
        entries.add("2000 - name5");

        Comparator<String> comparator = new MyComparator();
        Collections.sort(entries, comparator );

        for (String e : entries){
            System.out.println(e);
        }

    }