(wip) BUG: itertuples was retuning empty list if frame had no columns

doc/source/whatsnew/v1.1.0.rst

@@ -249,6 +249,7 @@ Other
   instead of ``TypeError: Can only append a Series if ignore_index=True or if the Series has a name`` (:issue:`30871`)
 - Set operations on an object-dtype :class:`Index` now always return object-dtype results (:issue:`31401`)
 - Bug in :meth:`AbstractHolidayCalendar.holidays` when no rules were defined (:issue:`31415`)
+- Bug in :meth:`DataFrame.itertuples` was returning empty list when DataFrame has no columns (:issue:`25408`)
 -
 
 .. ---------------------------------------------------------------------------

pandas/core/frame.py

@@ -1027,7 +1027,11 @@ def itertuples(self, index=True, name="Pandas"):
             fields.insert(0, "Index")
 
         # use integer indexing because of possible duplicate column names
-        arrays.extend(self.iloc[:, k] for k in range(len(self.columns)))
+        if len(self.columns) > 0:
+            arrays.extend(self.iloc[:, k] for k in range(len(self.columns)))
+        else:
+            arrays.extend([() for _ in range(len(self))])
+            return iter(arrays)
 
         # Python versions before 3.7 support at most 255 arguments to constructors
         can_return_named_tuples = PY37 or len(self.columns) + index < 255

pandas/tests/frame/methods/test_to_dict.py

@@ -262,3 +262,10 @@ def test_to_dict_orient_dtype(self):
                 "c": type(df_dict["c"]),
             }
             assert result == expected
+
+    def test_to_dict_no_rows_split(self):
+        # GH 25408
+        columns = ["A", "B"]
+        result = DataFrame(columns=columns).transpose().to_dict(orient="split")
+        expected = {"index": ["A", "B"], "columns": [], "data": [[], []]}
+        assert result == expected

pandas/tests/frame/test_api.py

@@ -286,6 +286,12 @@ def test_itertuples(self, float_frame):
         else:
             assert not hasattr(result_255_columns, "_fields")
 
+        # GH 25408
+        df_0_columns = DataFrame(index=["A", "B"])
+        result = list(df_0_columns.itertuples())
+        tm.assert_index_equal(result[0], pd.Index(["A", "B"]))
+        assert result[1:] == [(), ()]
+
     def test_sequence_like_with_categorical(self):
 
         # GH 7839