Vector and Array please help

[jay lai]

Hello there,
I have a vector, and Array size of 4
I loops through the vector.size() and I need assigned the value of each element in the array to the value in the vector.
String [] arr = new String[4];
for (int x=0;x<myVector.size();x++)
{
what do i do here? thanks
}

The scenario is: on the web application, allow to add multi user, and each user allow to enter their id1,id2,id3,id4. I need to collect info of user1 associated with 4 ids, user2 with 4 ids...so on...Right now user is a Vector, and String [] ids = new String[4];

Please giving some help or thought, Many thanks in advance

[Kashyap Hosdurga]

Jay,
You may have to use Map structure to map user and his 4 IDs.
Say User1 - ID1, ID2, ID3, ID4
User2 - ID5, ID6, ID7, ID8

If thi is the case then you can add the Map to a vector using
addAll(int index, Collection c)
Please correct me if I am wrong.

[Srinivas Kalvala]

Hi,

String [] arr = new String[4];
for (int x=0;x<myVector.size();x++)
{
arr[x]=new String();
arr[x]=(String)myVector.get(x);
}

Thank you.

[Jesper de Jong]

Srinivas, the first of your two lines does not make sense:

arr[x]=new String();
arr[x]=(String)myVector.get(x);

Why are you first creating a new String, and immediately after that you throw away the String and assign some other value to arr[x]? Just leave out the first of these two lines.

[Jesper de Jong]

Originally posted by jay lai:
Hello there,
I have a vector, and Array size of 4
I loops through the vector.size() and I need assigned the value of each element in the array to the value in the vector.

What do you want - do you want to copy the content of the *array* into the *vector* or is it the other way around? In your sentence here you are saying array to vector, but your source code suggests vector to array.

Class Vector has a toArray() method, so you don't have to write the loop yourself. Unfortunately the code is a bit tricky if you want an array of a specific type (a String array, in your case):

String[] arr = (String[]) myVector.toArray(new String[0]);

[Madhura Prakash]

Hello,

Incase you want to copy the contents of the Vector to the Array you could also do it in the following manner,

Code:
----------------------------------------------------------------------------
String[] strCopiedFromVect = new String[vectorToBeCopied.size()];
vectorToBeCopied.copyInto(strCopiedFromVect);
----------------------------------------------------------------------------

Hope this helps..

Regards,
Madhura.

[Jeff Albertson]

public static List<String> arrayToList1(String[] array) {
   return Arrays.asList(array);
}
 
public static List<String> arrayToList2(String[] array) {
   return new ArrayList<String>(Arrays.asList(array));
}
 
public static String[] listToArray(List<String> list) {
    return list.toArray(new String[list.size()]);
}

These examples are in Java 5. The list returned by arrayToList1 is backed by the array. If that is not desired, the second version can be used.