Api update

merge request so that you can comment the code ;)

km3io/aanet.py

@@ -102,7 +102,7 @@ class Reader(AanetKeys):
             path-like object that points to the file of ineterst.
         """
         super().__init__(file_path)
-        self._lazy_data = uproot.open(self._file_path)['E'].lazyarrays()
+        self._data = uproot.open(self._file_path)['E'].lazyarrays()
 
     def __getitem__(self, key):
         """reads data stored in the branch of interest in an event tree.
@@ -132,7 +132,7 @@ class Reader(AanetKeys):
         if key not in self.valid_keys and not isinstance(key, int):
             raise KeyError(
                 "'{}' is not a valid key or is a fake branch.".format(key))
-        return self._lazy_data[key]
+        return self._data[key]
 
 
 class AanetReader(AanetKeys):
@@ -147,9 +147,9 @@ class AanetReader(AanetKeys):
         """
         super().__init__(file_path)
         if data is not None:
-            self._lazy_data = data
+            self._data = data
         else:
-            self._lazy_data = uproot.open(self._file_path)['E'].lazyarrays()
+            self._data = uproot.open(self._file_path)['E'].lazyarrays()
         self._events = None
         self._hits = None
         self._tracks = None
@@ -161,14 +161,14 @@ class AanetReader(AanetKeys):
 
     def __getitem__(self, item):
         return AanetReader(file_path=self._file_path,
-                           data=self._lazy_data[item])
+                           data=self._data[item])
 
     @property
     def events(self):
         if self._events is None:
             self._events = AanetEvents(
                 self.events_keys,
-                [self._lazy_data[key] for key in self.events_keys])
+                [self._data[key] for key in self.events_keys])
         return self._events
 
     @property
@@ -176,7 +176,7 @@ class AanetReader(AanetKeys):
         if self._hits is None:
             self._hits = AanetHits(
                 self.hits_keys,
-                [self._lazy_data[key] for key in self.hits_keys])
+                [self._data[key] for key in self.hits_keys])
         return self._hits
 
     @property
@@ -184,7 +184,7 @@ class AanetReader(AanetKeys):
         if self._tracks is None:
             self._tracks = AanetTracks(
                 self.tracks_keys,
-                [self._lazy_data[key] for key in self.tracks_keys])
+                [self._data[key] for key in self.tracks_keys])
         return self._tracks
 
     @property
@@ -192,7 +192,7 @@ class AanetReader(AanetKeys):
         if self._mc_hits is None:
             self._mc_hits = AanetHits(
                 self.mc_hits_keys,
-                [self._lazy_data[key] for key in self.mc_hits_keys])
+                [self._data[key] for key in self.mc_hits_keys])
         return self._mc_hits
 
     @property
@@ -200,7 +200,7 @@ class AanetReader(AanetKeys):
         if self._mc_tracks is None:
             self._mc_tracks = AanetTracks(
                 self.mc_tracks_keys,
-                [self._lazy_data[key] for key in self.mc_tracks_keys])
+                [self._data[key] for key in self.mc_tracks_keys])
         return self._mc_tracks
 
 
@@ -261,14 +261,14 @@ class AanetHits:
         return AanetHit(self._keys, [v[item] for v in self._values])
 
     def __len__(self):
-        return len(
-            self._values[0]
-        )  # I don't like this being explicit, what if values is empty ...
-
+        try:
+            return len(self._values[0])
+        except IndexError:
+            return 0
     def __str__(self):
         # hits
         if all(key.startswith('hits.') for key in self._keys):
-            return "Number of hits in the selected event: {}".format(len(self))
+            return "Number of hits: {}".format(len(self))
         # mc hits
         if all(key.startswith('mc_hits.') for key in self._keys):
             return "Number of mc hits in the selected event: {}".format(