Add Branch.is_single

km3io/rootio.py

@@ -187,6 +187,15 @@ class Branch:
                     self._branch[self._keymap['id']].lazyarray(
                         basketcache=BASKET_CACHE), self._index_chain))
 
+    @property
+    def is_single(self):
+        """Returns True when a single branch is selected."""
+        if len(self._index_chain) > 0:
+            if isinstance(self._index_chain[-1], (int, np.int32, np.int64)):
+                return True
+        return False
+
+
     def __iter__(self):
         self._iterator_index = 0
         return self