better handling of empty storage and improved addition of new elements

storage.py

@@ -188,11 +188,14 @@ class DataStorage(dict):
     self.update( **dict(d) )
 
   def __setitem__(self, key, value):
+    #print("__setitem__")
     setattr(self,key,value)
     super().__setitem__(key, value)
 
   def __setattr__(self, key, value):
     """ allows to add fields with data.test=4 """
+    #print("__setattr__")
+    if isinstance(value,(dict,collections.OrderedDict)): value = DataStorage(value)
     super().__setitem__(key, value)
     super().__setattr__(key,value)
 
@@ -208,23 +211,33 @@ class DataStorage(dict):
   def __repr__(self):
     keys = list(self.keys())
     keys.sort()
+    if len(keys) == 0: return "Empty DataStorage"
     nchars = max(map(len,keys))
     fmt = "%%%ds %%s" % (nchars)
     s = ["DataStorage obj containing (sorted): ",]
     for k in keys:
-      if isinstance(self[k],np.ndarray):
-        value_str = "array, size %s, type %s"% ("x".join(map(str,self[k].shape)),self[k].dtype)
-      elif isinstance(self[k],DataStorage):
-        value_str = str(self[k])[:50] + "..."
-      elif isinstance(self[k],(str,DataStorage)):
-        value_str = self[k][:50] + "..."
+      obj = self[k]
+      if isinstance(obj,np.ndarray):
+        value_str = "array, size %s, type %s"% ("x".join(map(str,obj.shape)),obj.dtype)
+      elif isinstance(obj,DataStorage):
+        value_str = str(obj)[:50]
+      elif isinstance(obj,(str,DataStorage)):
+        value_str = obj[:50] 
+      elif isinstance(obj,(list,tuple)) and all( [isinstance(v,np.ndarray) for v in obj]):
+        value_str = "list of arrays, shapes " + ",".join([str(v.shape) for v in obj[:5]]) + " ..."
       elif self[k] is None:
         value_str = "None"
       else:
         value_str = str(self[k])
+      if len(str(obj))>50: value_str += " ..."
       s.append( fmt % (k,value_str) ) 
     return "\n".join(s)
 
+  def keys(self):
+    keys = list(super().keys())
+    keys = [k for k in keys if k != 'filename' ]
+    return keys
+
   def save(self,fname=None):
     if fname is None: fname = self.filename
     assert fname is not None