Vector to String[] Conversion
Hi All,
I am trying to convert Vector to String Array. the problem is when I tried to print the String Array out side the loop I am getting only last value.
I want to pass String Array to another function.
How to do that?
Find the code below:-
Vector vec=new Vector()
vec.add("abc\\aa.doc");
vec.add("abc\\ccc.doc");
vec.add("abc\\bb.doc");
String [] arr=new String[vec.size()];
for(int i=0;i<=vec.size();i++){
arr[i]=vec.get(i).toString();
}
System.out.println("ARRAY"+ arr);
Current Output
Output :- ARRAY abc\\bb.doc
Desired Output
ARRAY abc\\aa.doc,,abc\ccc.doc,abc\\bb.doc
Thanks.
List < String > vec=new Vector< String > ();
vec.add("abc\\aa.doc");
vec.add("abc\\ccc.doc");
vec.add("abc\\bb.doc");
String[] arr = vec.toArray(new String[0]);
Or, if you are using an old version of Java:
List vec=new ArrayList ();
vec.add("abc\\aa.doc");
vec.add("abc\\ccc.doc");
vec.add("abc\\bb.doc");
String[ ] arr = (String[ ]) vec.toArray(new String[0]);
Thanks for the early reply
But,
If you see the code again, you will find that I am trying to print the values of ARRAY outside the for loop
for(int i=0;i<=vec.size();i++){
arr[i]=vec.get(i).toString();
}
System.out.println( "ARRAY"+ arr);
Even with your code I am getting the same result.
Current Output
Output :- ARRAY abc\\bb.doc
I want full vector converted to String Array out side the loop.
Desired Output
ARRAY abc\\aa.doc,,abc\ccc.doc,abc\\bb.doc
Thanks
Why print out the values in the array, when you can print out the values in a collection so much more easily:System.out.println( "collection: "+ vec);
The point is I have to pass String[] to a function, but all the values are there in Vector. So I need to convert vector into String[].Thanks.
Object[] o=vector.toArray();String[] s=new String[o.length];System.arraycopy(o,0,s,0,o.length);myFunctionThatTakesAStringArray(s);
my previous code assumes that the Vector contains String objects
> Object[] o=vector.toArray();
> String[] s=new String[o.length];
> System.arraycopy(o,0,s,0,o.length);
>
> myFunctionThatTakesAStringArray(s);
Replies #1 (or #2) are better solutions because you don't go through the
silliness of copying from one array to another.
Can you pass a List to this function?
public static void someSillyFunction(String[] args)
{
}
I thought I read that the OP needs to pass a the result to a method that takes String[].
If that is not the case, you are most likely right...
You should always post the real code you're using.
The code as you posted would throw an exception since you're trying to access the vector outside it's boundaries.
Your code:
for(int i=0;i<=vec.size();i++){
arr[i]=vec.get(i).toString();
}
Correct code:
for(int i = 0;i < vec.size(); i++) {
arr[i] = vec.get(i).toString(); // or cast to String
Object[] o=vector.toArray();String[] s=new String[o.length];System.arraycopy(o,0,s,0,o.length);myFunctionThatTakesAStringArray(s);Hi ,I am getting an errorjava.lang.ArrayStoreException when I use the above code..Any other solution
This assumes vec contains only Strings.String[ ] arr = (String[ ]) vec.toArray(new String[0]);Second verse, same as the first.
OK,
My vector contains Objects...
I tried to use the following code
String[] attachments = new String[setOfHandle.size()];
for (int i = 0; i < setOfHandle.size(); i++) {
attachments[i] = String.valueOf(setOfHandle.get(i));
// if attachments exists, add them
if ( attachments != null ) {
addAtta( maild, attachments );
checkPoint = false;
}
}
In the above code setOfHandle is a vector contains objects.. I need to convert it to String[] and pass it to addAtta.
While doing this I am getting an error
java.lang.ArrayIndexOutOfBoundsException: 1
What version of Java are you using?
I'm not totall sure I understand your problem, but if it's what I think it is:
1) Determine the size of the Vector.
2) Create a new String[] of that size.
3) Iterate over the Vector
3.1) For each element in the Vector, call its toString and put the results into the current array slot. If you want null to go in as null, check first before calling toString. If you want it to go in as "null", don't bother checking, and call String.valueOf instead of toString.
jverda at 2007-7-21 21:05:24 >
> While doing this I am getting an error
> java.lang.ArrayIndexOutOfBoundsException: 1
You're trying to access the second element (index 1) of an array that has a length less than 2. Look at the details of the stack trace. It's already telling you what you did wrong. If you look more closely, you'll see exactly where it went wrong and what called what to get there.
jverda at 2007-7-21 21:05:24 >
String[] attachments = new String[setOfHandle.size()];
for (int i = 0; i < setOfHandle.size(); i++) {
attachments[i] = String.valueOf(setOfHandle.get(i));
}
It's a mystery to me what you are doing testing "attachments != null" in that loop. I suggest you stop that.
> > String[] attachments = new
> String[setOfHandle.size()];
> for (int i = 0; i < setOfHandle.size(); i++) {
> attachments[i] =
> String.valueOf(setOfHandle.get(i));
>
>
> It's a mystery to me what you are doing testing
> "attachments != null" in that loop. I suggest you
> stop that.
He'd need to test if he wanted null instead of "null" if any of the Vector's elements could be null.
jverda at 2007-7-21 21:05:24 >
oops mistakeIf condition is outside the for loop.Hippolyte :- Still I am getting the same errorjverd - you are right I am exactly looking for that.
My code works when I run it:
import java.awt.Point; //for example
import java.util.*;
public class ToArrayExample {
public static void main(String[] args) {
List list = new ArrayList();
list.add(new Point(1,2));
list.add(null);
list.add(new Point(3,4));
String[] arr = new String[list.size()];
for (int i = 0; i < list.size(); i++) {
arr[i] = String.valueOf(list.get(i));
}
//print out
for(int i = 0; i < arr.length; ++i) {
System.out.println(arr[i]);
}
}
}
I know it works fine,But if you have to pass your String[] (In you example arr) to a function how you do that?
In the usual way:
import java.awt.Point; //for example
import java.util.*;
public class ToArrayExample {
public static void main(String[] args) {
List list = new ArrayList();
list.add(new Point(1,2));
list.add(null);
list.add(new Point(3,4));
String[] arr = new String[list.size()];
for (int i = 0; i < list.size(); i++) {
arr[i] = String.valueOf(list.get(i));
}
display(arr);
}
public static void display(String[] s) {
for(int i = 0; i < s.length; ++i) {
System.out.println(s[i]);
}
}
}
Thanks Hippolyte , I am doing exactly what you have shown ..but still I am getting the same error .. Now I predict probably its a problem with external API what I am using.I was cross checking my self ....Anyway Thanks.
> In the usual way:for (int i = 0; i < list.size(); i++) {arr[i] = String.valueOf(list.get(i));}And this executes faster than arraycopy?
> And this executes faster than arraycopy?Maybe.
