Add Primitive Array to Linked List

Question

I am trying to add an array of integers to a Linked List. I understand that primitive types need a wrapper which is why I am trying to add my int elements as Integers. Thanks in advance.

int [] nums = {3, 6, 8, 1, 5};

LinkedList<Integer>list = new LinkedList<Integer>();
for (int i = 0; i < nums.length; i++){

  list.add(i, new Integer(nums(i)));

Sorry - my question is, how can I add these array elements to my LinkedList?

you could try list.add(new Integer(nums(i))) but it seems alright to me as it is. Your question is if there is a one-line way to add this array of primitives into a collection of Integers? — Leo
– Leo, Commented Feb 1, 2014 at 2:04
By the way, you can also just do LinkedList<Integer> list = new LinkedList<Integer>(Arrays.asList(nums)); — Zach Langley
– Zach Langley, Commented Feb 1, 2014 at 3:06
Its "expensive" to use list.add(i, new Integer(nums(i)) (accessing by index) in LinkedList. Just use list.add(new Integer(nums(i)). — Ashot Karakhanyan
– Ashot Karakhanyan, Commented Feb 1, 2014 at 9:36

Niklas R · Accepted Answer · 2014-02-01 08:54:49Z

8

You are doing it correctly except change this line

list.add(i, new Integer(nums(i)));  // <-- Expects a method

to

list.add(i, new Integer(nums[i]));

or

list.add(i, nums[i]);  // (autoboxing) Thanks Joshua!

edited Feb 1, 2014 at 8:54

Niklas R

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answered Feb 1, 2014 at 2:10

Prince

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1 Comment

Joshua Taylor Over a year ago

With auto boxing, you shouldn't even need to make a new integer object

Ashot Karakhanyan · Accepted Answer · 2014-02-01 09:26:47Z

2

If you use Integer array instead of int array, you can convert it shorter.

Integer[] nums = {3, 6, 8, 1, 5};      
final List<Integer> list = Arrays.asList(nums);

Or if you want to use only int[] you can do it like this:

int[] nums = {3, 6, 8, 1, 5};
List<Integer> list = new LinkedList<Integer>();
for (int currentInt : nums) {
    list.add(currentInt);
}

And use List instead LinkedList in the left side.

edited Feb 1, 2014 at 9:26

answered Feb 1, 2014 at 9:13

Ashot Karakhanyan

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1 Comment

Tuxino Over a year ago

Thanks Ashot, we were asked to use an int array to solve the problem so your second response would be acceptable in this case.

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