Possible Duplicate:
convert String arraylist to string array in java?
Following is my code
ArrayList<String> IdList = new ArrayList<String>(); and I want to copy items from IDList to int IdArray[].
- int[] or String[] array?Prince John Wesley– Prince John Wesley2011-10-14 09:05:45 +00:00Commented Oct 14, 2011 at 9:05
- Actually i want it int array. but String[] is also fine.Soniya– Soniya2011-10-14 09:06:49 +00:00Commented Oct 14, 2011 at 9:06
- You should start with an ArrayList<int> in the first place if it doesn't matter XDRob– Rob2011-10-14 09:08:57 +00:00Commented Oct 14, 2011 at 9:08
- @ All: Thanks for your help. Following code helped me out String[] array = Idlist.toArray(new String[list.size()]);Soniya– Soniya2011-10-14 10:08:32 +00:00Commented Oct 14, 2011 at 10:08
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6 Answers
Try this stuff,
int arr[] = new int[arrList.size()]; for (int i = 0; i < arrList.size(); i++) { arr[i] = Integer.parseInt(arrList.get(i)); } 
3 Comments
Soniya
gave ArrayIndexOutOfBoundException
Soniya
int asize= IdList.size(); int arr[] = new int[asize]; for (int i = 0; i < asize); i++) { arr[i] = Integer.parseInt(IdList.get(i)); }
Soniya
ArrayList<String> IdList = new ArrayList<String>(); int IdArray[]. for (int i = 0; i < IdList.size(); i++) { IdArray[i] = (int)IdList.get(i)); } 
Comments
I think you must iterate through all items, which are Strings, and parse each of them into an int to populate your new int[] array.
1 Comment
Soniya
Did you mean, Iterator itr = IdList.iterator(); int IdArray[]={}; int d=0; while(itr.hasNext()) { String topic_id = (String) itr.next(); IdArray[d]= Integer.parseInt(topic_id); d++; System.out.print("============"+topic_id ); }
// String array String[] arr = idList.toArray(new String[0]); // for int array int[] iarr = new int[arr.length]; int idx = 0; for(String s : arr) { iarr[idx++] = Integer.parseInt(s); } answered Oct 14, 2011 at 9:08
Prince John Wesley
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Comments
String [] outStrArray = (String [])IdList.toArray()
1 Comment
x4u
This will throw a ClassCastException because
Collection.toArray() returns a Object[].int[] IdArray = IdList.toArray(); However, this will probably fail because you're trying to convert a string-arraylist to an int-array..
