public MathList<Variable> VariableList(){
        MathList<Variable> variable = new MathList<Variable>();
        for (int i = 0; i < table.getRowCount(); i++) {
                if ((table.getValueAt(i, 0) == null) == false) {
                    variable.add(new Variable(table.getValueAt(i, 0).toString().charAt(0), Double.valueOf(table.getValueAt(i, 1).toString())));
                } else {
                    break;
                }
            }
        return variable;
    }