Minor bug fixes for the export of data into csv files

+export/Data.m

@@ -3,9 +3,9 @@ classdef (Abstract) Data < handle & matlab.mixin.Heterogeneous
     %   Detailed explanation goes here
     
     properties
-        basepath = '.';
-        foldername = '.';
-        filename = 'data';
+        basepath char = '.';
+        foldername char = '.';
+        filename char = 'data';
         N = 201;        
     end
         
@@ -53,7 +53,7 @@ classdef (Abstract) Data < handle & matlab.mixin.Heterogeneous
             for k = 1:length(obj)
                if ~obj(k).isempty
                    
-                  if ~isdir(obj(k).absolutepath)
+                  if ~isfolder(obj(k).absolutepath)
                      mkdir(obj(k).absolutepath); 
                   end
                    

+quantity/Discrete.m

@@ -190,7 +190,7 @@ classdef  (InferiorClasses = {?quantity.Symbolic}) Discrete ...
 					headers{i+1} = obj(i).name + "" + num2str(i);
 				end
 				exportData = export.dd(...
-					'M', [obj.grid{:}, obj.valueDiscrete], ...
+					'M', [obj(1).grid{:}, obj.valueDiscrete], ...
 					'header', headers, varargin{:});
 			elseif obj.nargin == 2
 				error('Not yet implemented')