Copystored array value into arraylist JAVA

Question

I have a int array with 2 number. I wan to copy this number into array list and print them out. as much as possible refrain from using Integer result[];

  int result[] = {1024,2048};
  List<Integer> res = new ArrayList<Integer>(result);


public class TEA {

    /**
     * @param args
     */
    public static void main(String[] args) {

          int result[] = {1024,2048};
          List<int[]> res = Arrays.asList(result);
          System.out.println(res);


    }

}

output :[[I@3312b1dd]

Louis Wasserman · Accepted Answer · 2013-05-10 16:55:02Z

1

If you can't make result into an Integer[] instead of an int[], your options are either to do an explicit for loop:

List<Integer> list = new ArrayList<Integer>();
for (int value : array) {
  list.add(value);
}

...or, if you can use third-party libraries, use Guava's Ints.asList(int[]). That's more or less the entire space of your options.

answered May 10, 2013 at 16:55

Louis Wasserman

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2 Comments

newbieprogrammer Over a year ago

this is to add in new value,so it is not possible to copy existing array without using Integer result[]?

Louis Wasserman Over a year ago

...I'm not sure what you're saying. These are essentially the only options if you want to get an int[] to a List<Integer>, but it's not clear what you mean by "this is to add in new value."

AllTooSir · Accepted Answer · 2013-05-10 17:07:39Z

0

Use Arrays.asList() method to do the same.

List<Integer> res = Arrays.asList(result);

This is a list view of the array, you can't add or delete elements.

List<Integer> res = new ArrayList<Integer>(Arrays.asList(result));

Copies all elements from the source array into a new list.

EDITED:

There is no automatic conversion from array of primitive type to array of their wrapper reference types.

int result[] = {1024,2048};
List<Integer> list = new ArrayList<Integer>();
for (int value : result) {
    list.add(value);
}
System.out.println(list);

edited May 10, 2013 at 17:07

answered May 10, 2013 at 16:30

AllTooSir

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2 Comments

newbieprogrammer Over a year ago

not working for both...i getting error, i also tired changing integer to int[], it return some rubbish value

newbieprogrammer Over a year ago

Exception in thread "main" java.lang.Error: Unresolved compilation problem: Type mismatch: cannot convert from List<int[]> to List<Integer> at TEA.main(TEA.java:74)

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