BUG: Fixes #62775 - DataFrame.from_dict() drops empty rows with orient='index'

doc/source/whatsnew/v3.0.3.rst

@@ -46,6 +46,7 @@ Bug fixes
 - Fixed :class:`ArrowDtype` string arithmetic for addition between ``string`` and ``large_string`` typed arrays (:issue:`65220`)
 - Fixed a bug in adding missing values (e.g. :attr:`NA`) to a pyarrow-backed string array or Series
   raising an error instead of propagating the missing value (:issue:`64968`)
+- Fixed a bug in :meth:`DataFrame.from_dict` where rows corresponding to an empty :class:`Series` or ``dict`` are dropped when ``orient='index'`` (:issue:`62775`)
 - Fixed a bug in :meth:`Series.rank` with period dtype and missing values, always sorting missing values at the top, regardless of the ``na_option`` value (:issue:`64976`)
 - Fixed a bug in reading files with a chained URL scheme (e.g. ``tar://``) with the latest version of ``fsspec`` (:issue:`65462`).
 - Fixed a hang in :meth:`Series.str.replace` for PyArrow-backed string data when replacing an empty pattern; behavior now matches Python's ``str.replace`` (:issue:`64941`).

pandas/core/frame.py

@@ -19011,13 +19011,20 @@ def values(self) -> np.ndarray:
 
 
 def _from_nested_dict(
-    data: Mapping[HashableT, Mapping[HashableT2, T]],
-) -> collections.defaultdict[HashableT2, dict[HashableT, T]]:
-    new_data: collections.defaultdict[HashableT2, dict[HashableT, T]] = (
+    data: Mapping[HashableT, Mapping[HashableT2, T | None]],
+) -> collections.defaultdict[HashableT2, dict[HashableT, T | None]]:
+    new_data: collections.defaultdict[HashableT2, dict[HashableT, T | None]] = (
         collections.defaultdict(dict)
     )
+    cols = []
+    for s in data.values():
+        for col in s.keys():
+            if col not in cols:
+                cols.append(col)
+
     for index, s in data.items():
-        for col, v in s.items():
+        for col in cols:
+            v = s.get(col, None)
             new_data[col][index] = v
     return new_data
 

pandas/tests/frame/constructors/test_from_dict.py

@@ -44,6 +44,18 @@ def test_constructor_single_row(self):
         ).reindex(result.index)
         tm.assert_frame_equal(result, expected)
 
+    def test_from_nested_dict_series_with_empty_series(self):
+        data = {"good": Series({"a": 1, "b": 2}), "blank": Series()}
+
+        result = DataFrame.from_dict(data, orient="index")
+        expected = DataFrame(
+            {
+                "a": {"good": 1.0, "blank": np.nan},
+                "b": {"good": 2.0, "blank": np.nan},
+            }
+        )
+        tm.assert_frame_equal(result, expected)
+
     def test_constructor_list_of_series(self):
         data = [
             OrderedDict([["a", 1.5], ["b", 3.0], ["c", 4.0]]),