BUG: accept empty list to DataFrame constructor, regression from 0.6.0, GH #491

Author: wesm

pandas/core/frame.py

@@ -207,7 +207,7 @@ def __init__(self, data=None, index=None, columns=None, dtype=None,
                 mgr = self._init_ndarray(data, index, columns, dtype=dtype,
                                          copy=copy)
         elif isinstance(data, list):
-            if isinstance(data[0], (list, tuple)):
+            if len(data) > 0 and isinstance(data[0], (list, tuple)):
                 data, columns = _list_to_sdict(data, columns)
                 mgr = self._init_dict(data, index, columns, dtype=dtype)
             else:

pandas/tests/test_frame.py

@@ -1222,6 +1222,11 @@ def test_constructor_more(self):
         self.assertEqual(len(dm.columns), 2)
         self.assert_(dm.values.dtype == np.float64)
 
+    def test_constructor_empty_list(self):
+        df = DataFrame([], index=[])
+        expected = DataFrame(index=[])
+        assert_frame_equal(df, expected)
+
     def test_constructor_list_of_lists(self):
         # GH #484
         l = [[1, 'a'], [2, 'b']]