Store data in dynamic 2D Array

Question

I have a list of people like this List<People>. Now I have to split this list by the gender of each person. After that I want to have one 2D Object. In the first dimenson is the gender and in the second the people itself.

My problem now is that I do not know how to store the data. I have to add and remove items from the second dimenson later and it would be nice if can get the Items with [][] or (gender, position). I thought about nested ArrayLists but I think that is an unpleasant solution. How would you solve this?

Answer 1

UPDATE

If you want that notation, use a Map of arrays encapsulated in a "custom" collection of objects like this:

enum Gender {
    MALE, FEMALE
}

class MyInfo {

    private Map<Gender, List<Person>> myInfo;

    public MyInfo(List<Person> females, List<Person> males) {
        myInfo = new HashMap<Gender, List<Person>>();
        myInfo.put(Gender.MALE, males);
        myInfo.put(Gender.FEMALE, females);
    }

    public Person get(Gender gender, int index) {
        myInfo.get(gender).get(index);
    }

}

and refer each person as:

Person selectedPerson = myInfo.get(Gender.MALE, 100);

Answer 2

I would create my own data structure like this:

public class PeopleList {

    private List<Person> men;
    private List<Person> women;

    public Person get(char gender, int position){
        switch (gender){
            case 'M': 
                return men.elementAt(position);
            case 'W': 
                return women.elementAt(position);
        }
    }

    public void insert(Person p){
        switch(p.getGender()){
            case 'M': 
                men.insert(p);
                break;
            case 'W': 
                women.insert(p);
                break;
        }
    }
}