Question

I have really stuck on two Java related issues. One simple and one more difficult.

Regarding the creation of a 2D array, I initialize a table like this:

private String [][] table_of_classifiers = null;

and then, within a function, I fill its contents like this:

        String [][] table_of_classifiers = {
            {"x1","x","x","x","x"},
            {"x2","x","x","x","x"},
            {"x3","x","x","x","x"},
            {"x4","x","x","x","x"},
            {"x5","x","x","x","x"},
            {"x6","x","x","x","x"},
        };

But as you can guess the second table overwrites (locally) the first one, that is of course not what I want to do. What I do wrong? Note that the dimension of the table is not known from the beginning.

Answer 1

Just do:

class Foo {
    private String [][] table_of_classifiers = null;

    void bar() {
        table_of_classifiers = new String[][] {
                    {"x1","x","x","x","x"},
                    {"x2","x","x","x","x"},
                    {"x3","x","x","x","x"},
                    {"x4","x","x","x","x"},
                    {"x5","x","x","x","x"},
                    {"x6","x","x","x","x"},
        };
    }
}

Java doesn’t have eval (because it’s a compiled language), but it does have reflection. It’s almost certainly not the best approach to whatever it is that you want to do, though.