Parse a table from stdin

Question

From stdin input line by line get a table like:

3 9 $12  $7  $2
4 $5  1 $4  $21
12  $11 0 0  $17

I need to parse it in a such way, so that I will have two 2d lists: 1) Just a table of numbers:

3 9 12 7 2
4 5 1 4 21
12 11 0 0 17

2) table, in which true will mean that there was a dollar sign in front of a number:

false false true true true
false true false true true
false true false false true

Which is the best way to do this?

I've had the following code:

public static List[] parseTable() {
    ArrayList<ArrayList<Integer>> vals = new ArrayList<>();
    ArrayList<ArrayList<Boolean>> truthtable = new ArrayList<>();
    BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
    String mark = "$";
    try {
        while (true) {
            String[] splitline = reader.readLine().split("\\s+");
            ArrayList<Integer> valsrow = new ArrayList<>();
            ArrayList<Boolean> truthrow = new ArrayList<>();
            System.out.println(Arrays.toString(splitline));
            for (String element: splitline) {
                if (element.startsWith(mark)) {
                    truthrow.add(true);
                }
                else {
                    truthrow.add(false);
                }
                valsrow.add(Integer.parseInt(el.replaceAll(mark, "")));
            }
            vals.add(valsrow); truthtable.add(truthrow);
        }
    }
    catch(IOException e) {
        List[] output = new List[2];
        res[0] = truthtable; res[1] = vals;
        return  output;
    }

but it does not correctly strip spaces and results in a

NumberFormatException: for input string: ""

I don't know the size of an input preliminarily.

Answer 1

After that I can't say more than Lutz Horn, it's the steps you have to do ;)

I made some small changes to your code and now it works for me ;)

    ArrayList<ArrayList<Integer>> vals = new ArrayList<ArrayList<Integer>>();
    ArrayList<ArrayList<Boolean>> truthtable = new ArrayList<ArrayList<Boolean>>();
    BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
    String mark = "$";
    try {
        while (true) {
            String[] splitline = reader.readLine().split("\\s+");
            ArrayList<Integer> valsrow = new ArrayList<Integer>();
            ArrayList<Boolean> truthrow = new ArrayList<Boolean>();
            for (String element: splitline) 
            {
                if(!element.isEmpty())
                {
                    if (element.startsWith(mark))
                    {
                        truthrow.add(true);
                        element = element.substring(1, element.length());
                    }
                    else 
                        truthrow.add(false);

                    valsrow.add(Integer.parseInt(element.trim()));
                }
            }
            vals.add(valsrow); 
            truthtable.add(truthrow);
        }
    }
    catch(IOException e) {
        System.out.println("prob");
    }

enjoy ;)