Add elements of one ArrayList to another ArrayList

Question

Is it possible to add the elements of one Arraylist to another Arraylist? For example if an Arraylist has elements 3,6,3,8,5 in index 0,1,2,3,4, now I want to add 3,6,3,8,5 to another ArrayList in index 0, is it possible?

ArrayList<String> num = new ArrayList<String>();
 num.add("3");
 num.add("6");
 num.add("3");
 num.add("8");
 num.add("5");
ArrayList<String> result = new ArrayList<String>();
 for (int i = 0; i < num.size(); i++)
 {
        result.addAll(i,num);   
 }

I have tried this but it is not working. what i want is when i try System.out.println(result.get(0)); result must be [3 6 3 8 5].

Answer 1

I think what you are trying to do is this:

for (int i = 0; i < num.size(); i++) {
    result.add(i, num.get(i)); 
}

Or maybe just this:

result.addAll(num);

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What your current code does is you add all of num to result many times ... at successive starting positions. That is ... strange.

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UPDATE

What i want is when i try System.out.println(result.get(0)); result must be [3 6 3 8 5].

Ah ... I get it ... you are trying to create a list of strings where the strings are representations of the input lists:

Do this:

for (int i = 0; i < num.size(); i++) {
    result.add(i, num.toString()); 
}

This will give you the output you are asking for.

Another possibility is that you want a list of lists of strings:

ArrayList<ArrayList<String>> result = new ArrayList<>();
for (int i = 0; i < num.size(); i++) {
    result.add(i, num); 
}

That will also give you the output you are asking for ... though for a different reason.