Made subtraction behavior consistent with addition

Author: jasonzutty

pandas/core/index.py

@@ -1141,7 +1141,10 @@ def __add__(self, other):
     __ge__ = _indexOp('__ge__')
 
     def __sub__(self, other):
-        return self.diff(other)
+        if isinstance(other, Index):
+            return self.diff(other)
+        else:
+            return Index(np.array(self) - other)
 
     def __and__(self, other):
         return self.intersection(other)