BUG: from_dataframe with empty objects (pandas-dev#53161)

* BUG: from_dataframe with empty objects

* Use protocol_df_chunk_to_pandas

Author: mroeschke

doc/source/whatsnew/v2.1.0.rst

@@ -488,6 +488,7 @@ Metadata
 Other
 ^^^^^
 - Bug in :class:`FloatingArray.__contains__` with ``NaN`` item incorrectly returning ``False`` when ``NaN`` values are present (:issue:`52840`)
+- Bug in :func:`api.interchange.from_dataframe` when converting an empty DataFrame object (:issue:`53155`)
 - Bug in :func:`assert_almost_equal` now throwing assertion error for two unequal sets (:issue:`51727`)
 - Bug in :func:`assert_frame_equal` checks category dtypes even when asked not to check index type (:issue:`52126`)
 - Bug in :meth:`DataFrame.reindex` with a ``fill_value`` that should be inferred with a :class:`ExtensionDtype` incorrectly inferring ``object`` dtype (:issue:`52586`)

pandas/core/interchange/from_dataframe.py

@@ -79,7 +79,9 @@ def _from_dataframe(df: DataFrameXchg, allow_copy: bool = True):
         raise RuntimeError(
             "To join chunks a copy is required which is forbidden by allow_copy=False"
         )
-    if len(pandas_dfs) == 1:
+    if not pandas_dfs:
+        pandas_df = protocol_df_chunk_to_pandas(df)
+    elif len(pandas_dfs) == 1:
         pandas_df = pandas_dfs[0]
     else:
         pandas_df = pd.concat(pandas_dfs, axis=0, ignore_index=True, copy=False)

pandas/tests/interchange/test_impl.py

@@ -272,3 +272,15 @@ def test_categorical_to_numpy_dlpack():
     result = np.from_dlpack(col.get_buffers()["data"][0])
     expected = np.array([0, 1, 0], dtype="int8")
     tm.assert_numpy_array_equal(result, expected)
+
+
+@pytest.mark.parametrize("data", [{}, {"a": []}])
+def test_empty_pyarrow(data):
+    # GH 53155
+    pytest.importorskip("pyarrow", "11.0.0")
+    from pyarrow.interchange import from_dataframe as pa_from_dataframe
+
+    expected = pd.DataFrame(data)
+    arrow_df = pa_from_dataframe(expected)
+    result = from_dataframe(arrow_df)
+    tm.assert_frame_equal(result, expected)