String from ArrayList to two dimensional array using Scanner

Question

I'm using Eclipse and I'm trying to take a string:

1 2 3 4

out of an ArrayList:

ArrayList strings = new ArrayList<>();

And store each number into a two dimensional array:

int size = (int) strings.get(0); // Represents the number of rows
int stringList[][] = new int[size][];

// Store results in a two dimensional array
for(int i = 0; i < size; i++){
    int index = i + 1; 
    String fish = (String) strings.get(index);

    Scanner npt = new Scanner(fish);

    for(int j = 0; npt.hasNext(); j++) {
        size[i][j] = Integer.parseInt(npt.next());
    }
}

This is the section that is causing the error:

// ERROR: The type of the expression must be an array type but it resolved to int
size[i][j] = Integer.parseInt(npt.next());

`size` is an `int`, you can't write `size[i][j]`. The error message is very clear. — Maroun, Nov 01 '15 at 07:33
Wow I must be completely out of it, I did not notice that at all. Sorry for wasting you guys time. — Stephen, Nov 01 '15 at 07:52

score 1 · Answer 1 · edited May 23 '17 at 12:14

strings is a raw type. Let's start by fixing that¹,

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

Then you can use Integer.parseInt(String) parse² the String to an int like

int size = Intger.parseInt(strings.get(0));

Then there's no need for a cast in

String fish = (String) strings.get(index);

You can use

String fish = strings.get(index);

etc.

^{1 _{And program to the List interface.}}
^{2 _{Not cast.}}

score 0 · Answer 2 · answered Nov 01 '15 at 07:35

0

You probably meant

stringList[i][j] = Integer.parseInt(npt.next());

though that wouldn't work either, unless you properly initialize the stringList array.

You would have to initialize stringList[i] (for each i) with something like stringList[i] = new String[someLength]; but I'm not sure which length you should use.

answered Nov 01 '15 at 07:35

Eran

387,369
54
702
768

Yea, sorry. I didn't notice my error. It's so obvious now, but before you guys pointed it out I didn't see it at all. – Stephen Nov 01 '15 at 07:54

String from ArrayList to two dimensional array using Scanner

2 Answers2