How to group array of objects ?

I have a big array of Student objects.  

Student object has a field coNo;

Now, I plan to group these Students into smaller arrays.  i.e Students who has same coNo should be in same group.

Finally I'd like to print these smaller arrays.


Issue  is , I'll have dynamic no of smaller arrays which I need to prepare from the bigger array. What is the way ?

using JDK 1.5
cofactorAsked:
Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

CEHJCommented:
You could use Map<String, List<Student>>, where the key is coNo. You can turn that List into Student[] if you really need to.
0

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
zzynxSoftware engineerCommented:
I'll have dynamic no of ...
Then a List is the most natural way to go (as CEHJ said)

The code looks something like:
Map<String, List<Student>> myMap = new HashMap();
for each student in your big array {
    if (!myMap.contains(student.getCoNo()) {
          List<Student> list = new ArrayList();
          list.add(student);
          myMap.put(student.getCoNo(), list);
    } else {
          myMap.get(student.getCoNo()).add(student);
    }
}

Open in new window

0
cofactorAuthor Commented:
Excellent
0
zzynxSoftware engineerCommented:
Thanx 4 axxepting
0
CEHJCommented:
:)
0
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Java

From novice to tech pro — start learning today.

Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.