CODEWITHSUNDEEP
javalistarraylist
Karen
Karen

Reputation: 122

Getting ArrayList Value Inside An ArrayList - Java

I have a problem with pulling out a value from an Arraylist inside an Arraylist. I'll just give an example of my problem.

Example:

ArrayList alA = new ArrayList();
ArrayList alB = new ArrayList();

alA.add("1");
alA.add("2");
alA.add("3");

alB.add(alA);

System.out.println(alB.get(0));

This will return [1, 2, 3] as the result.

In my case I only need to print out 3. How do I achieve this?

Upvotes: 1

Views: 277

Answers (3)

Md Johirul Islam
Md Johirul Islam

Reputation: 5162

Simply do the following if you don't want to change your other portions of current code

System.out.println(((ArrayList)alB.get(0)).get(2));

Upvotes: 3

Doga Oruc
Doga Oruc

Reputation: 816

System.out.println(alB.get(0)); return alB's 0th index element which is alA. Since you want the element 3, you need to get the 2nd index element of alA, in this case it is alA.get(2);

Combined: 

System.out.println(((ArrayList)alB.get(0)).get(2));

Upvotes: 2

Mureinik
Mureinik

Reputation: 311073

Just call get on the inner array:

System.out.println(((List) alB.get(0)).get(2));

Note that by using generics, you'll eliminate the need to cast:

List<String> alA = new ArrayList<>();
List<List<String>> alB = new ArrayList<>();

alA.add("1");
alA.add("2");
alA.add("3");

alB.add(alA);

System.out.println(alB.get(0).get(2));

Upvotes: 4

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