[FIX] Table: classes (Y) must be float

Author: jerneju

Orange/data/table.py

@@ -492,7 +492,7 @@ def from_numpy(cls, domain, X, Y=None, metas=None, W=None):
 
         if Y is None:
             if sp.issparse(X):
-                Y = np.empty((X.shape[0], 0), object)
+                Y = np.empty((X.shape[0], 0), dtype=np.float64)
             else:
                 Y = X[:, len(domain.attributes):]
                 X = X[:, :len(domain.attributes)]