How to change Vector to Array or ArrayList?

Question

I am trying to learn ArrayList and Vector. If for example I have private Vector cardsInMyHand; can I change it to ArrayList. As you see or I am wrong.

    private Vector numbers;
    .
    .
    .
    Vector studentNumbers;
    studentNumbers = new Vector();
    public int getNumbers(Vector studentNumbers, int x)
    {

       if (x >= 0 && x < studentNumber.size())
       {
          return ((Integer)hand.elementAt(x)).intValue();
       } else
         {
            return 0;
         }
   }

change to private ??????; ...... ArrayList<String> studentNumbers = new ArrayList<String>(); Can I do this ?

   public int getNumbers(ArrayList studentNumbers, int x)
   {

     if (x >= 0 && x < studentNumber.size())
     {
        return ((Integer)hand.elementAt(x)).intValue();
     } else
       {
        return 0;
       }
   }

Vector is a Collection so you can just do numbers.toArray(new String[numbers.size()]) to convert the Vector<String> to a String[] — D'Nabre
– D'Nabre, Commented Nov 5, 2014 at 4:13

Elliott Frisch · Accepted Answer · 2014-11-05 04:03:51Z

3

Yes, but your syntax has a few typos. And you should not use Raw Types. Finally, I suggest you use the List interface and read about Autoboxing and Unboxing.

public int getNumbers(List<Integer> studentNumbers, int x) {
    if (x >= 0 && x < studentNumbers.size()) {
        return studentNumbers.get(x);
    } else {
        return 0;
    }
}

answered Nov 5, 2014 at 4:03

Elliott Frisch

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3 Comments

JayLo Over a year ago

I don't understand about raw typesBox<String> stringBox = new Box<>(); Box rawBox = stringBox;

JayLo Over a year ago

you mean this is a raw type ArrayList<String> studentNumbers = new ArrayList<String>();

Elliott Frisch Over a year ago

@JayLo When you say just ArrayList objs; it is a raw type (it behaves like ArrayList<Object> objs;). The diamond operator on the right is short-hand, List<String> strings = new ArrayList<>(); for List<String> strings = new ArrayList<String>();.

Isuru Jayakantha · Accepted Answer · 2014-11-05 04:50:42Z

2

Check the below example with type safety.

public ArrayList<String> convertVectorToList(Vector<String> studentNoVec){
		   return new ArrayList<String>(studentNoVec); 
		}
	
	public static void main(String[] args) {
		Vector<String> v= new Vector<String>();
		v.add("No1");
		v.add("No2");
		Test a = new Test();
		for(String no : a.convertVectorToList(v)){
			System.out.println(no);
		}
	}

answered Nov 5, 2014 at 4:50

Isuru Jayakantha

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Comments

Isuru Jayakantha · Accepted Answer · 2014-11-05 04:27:26Z

0

First, Java Vector class considered obsolete or deprecated. If you want to convert Vector to an ArrayList use the below mentioned way. Simple and easy.

// convert vector to araryList  
public ArrayList convertVectorToList(Vector studentNoVec){
   return new ArrayList(studentNoVec); 
}

edited Nov 5, 2014 at 4:27

answered Nov 5, 2014 at 4:20

Isuru Jayakantha

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2 Comments

Elliott Frisch Over a year ago

Please do not use Raw Types.

Isuru Jayakantha Over a year ago

Yes! Its an example. Any Type can be used for Vector and ArrayList.

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