Multi-dimensional Java ArrayList (Declared element syntax)

Question

Is it possible to do the following?

private static ArrayList<integer<integer<String>>> myArrayList;

In other words, create an ArrayList with declared element syntax?

Example:

myArrayList[0][0] = "This is the string.";

If not, is it possible to do such with normal arrays?

Well have you tried it ? what results did you get ? and Integer will work much better than integer :) — giorashc, Oct 17 '12 at 16:25
`integer` should be `Integer` and also you cannot do `Integer`. that's not allowed. — Rohit Jain, Oct 17 '12 at 16:27
Is integer a user defined class? If not, your code won't even compile. Are you learning to program without writing programs? — Chetan Kinger, Oct 17 '12 at 19:01

score 1 · Answer 1 · answered Oct 17 '12 at 16:27

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It seems you are looking for multi-dimensional arrays in Java, declared as follows:

String [][] list = new String[10][10];
list[0][0] = "This is a string";
System.out.println(list[0][0]);

answered Oct 17 '12 at 16:27

Vikdor

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score 1 · Answer 2 · answered Oct 17 '12 at 16:27

You can declare List of List in the following way: -

List<List<String>> listOfList = new ArrayList<List<String>>();

Initialize your List, and then to add a String to your list element: -

listOfList.add(new ArrayList<String>());

listOfList.get(0).add("my String");

score 1 · Answer 3 · edited Oct 17 '12 at 16:30

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You can do

List<List<String>> list = new ArrayList<List<String>>();
list.add(new ArrayList<String>());

list.get(0).add("This is the string");

edited Oct 17 '12 at 16:30

jlordo

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answered Oct 17 '12 at 16:27

Peter Lawrey

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score 0 · Answer 4 · edited May 23 '17 at 12:27

0

What you would want to achieve in realtime?, Java defines set of APIs, which has its own usage and purpose. If you want to use multidimensional array, I would suggest to go for Object[][], though you should be able to declare

ArrayList list[][] = new ArrayList[5][7];

By doing so, you would be making you operation bit complex. And more over ArrayList is nothing but single dimensional Object array.

FYI

How to create a Multidimensional ArrayList in Java?

edited May 23 '17 at 12:27

Community

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answered Oct 17 '12 at 16:33

Satheesh Cheveri

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You've got the wrong syntax there unfortunately. Not sure what you mean by "achieve in realtime" either. – Paul Bellora Oct 18 '12 at 02:11
I dont understand by the comment 'wrong syntax', It is a valid java statement that can be compiled. – Satheesh Cheveri Oct 18 '12 at 06:17
It does compile but I don't think it's doing what you meant. `new ArrayList[5][7]` will instantiate an array of arrays of raw `ArrayList`s, which isn't what the OP wants. You probably meant what Peter and Rohit demonstrate. – Paul Bellora Oct 18 '12 at 06:22
That doesn't mean the syntax is wrong, agreed my answer is not that relevant OP's question. – Satheesh Cheveri Oct 18 '12 at 08:13

Multi-dimensional Java ArrayList (Declared element syntax)

4 Answers4