Fixes BUG producing float64 dtype when Dataframe is initialized with array of shape (0, 0)

doc/source/whatsnew/v2.2.0.rst

@@ -598,6 +598,7 @@ Other
 - Bug in :func:`infer_freq` and :meth:`DatetimeIndex.inferred_freq` with weekly frequencies and non-nanosecond resolutions (:issue:`55609`)
 - Bug in :meth:`DataFrame.apply` where passing ``raw=True`` ignored ``args`` passed to the applied function (:issue:`55009`)
 - Bug in :meth:`Dataframe.from_dict` which would always sort the rows of the created :class:`DataFrame`.  (:issue:`55683`)
+- Bug in ``dtype`` values inside a :class:`DataFrame` where initial provided dtype was lost when initializing empty DataFrame (:issue:`55649`)
 - Bug in rendering ``inf`` values inside a a :class:`DataFrame` with the ``use_inf_as_na`` option enabled (:issue:`55483`)
 - Bug in rendering a :class:`Series` with a :class:`MultiIndex` when one of the index level's names is 0 not having that name displayed (:issue:`55415`)
 - Bug in the error message when assigning an empty dataframe to a column (:issue:`55956`)

pandas/core/internals/construction.py

@@ -393,8 +393,18 @@ def ndarray_to_mgr(
         nb = new_block_2d(values, placement=bp, refs=refs)
         block_values = [nb]
 
-    if len(columns) == 0:
-        # TODO: check len(values) == 0?
+    if len(columns) == 0 and dtype is not None:
+        obj_columns = list(values)
+        block_values = [
+            new_block(
+                dtype.construct_array_type()._from_sequence(data, dtype=dtype),
+                BlockPlacement(slice(i, i + 1)),
+                ndim=2,
+            )
+            for i, data in enumerate(obj_columns)
+        ]
+
+    elif len(columns) == 0 and dtype is None:
         block_values = []
 
     return create_block_manager_from_blocks(

pandas/core/internals/managers.py

@@ -1683,10 +1683,14 @@ def as_array(
         passed_nan = lib.is_float(na_value) and isna(na_value)
 
         # TODO(CoW) handle case where resulting array is a view
-        if len(self.blocks) == 0:
+        if len(self.blocks) == 0 and dtype is None:
             arr = np.empty(self.shape, dtype=float)
             return arr.transpose()
 
+        elif len(self.blocks) == 0 and dtype is not None:
+            arr = np.empty(self.shape, dtype=dtype)
+            return arr.transpose()
+
         if self.is_single_block:
             blk = self.blocks[0]
 

pandas/tests/frame/test_constructors.py

@@ -2759,6 +2759,12 @@ def test_frame_string_inference_block_dim(self):
             df = DataFrame(np.array([["hello", "goodbye"], ["hello", "Hello"]]))
         assert df._mgr.blocks[0].ndim == 2
 
+    def test_frame_from_empty_array_perserving_dtype(self):
+        # GH#55649
+        np_list = [np.int8, np.int16, np.uint16, np.uint64]
+        for n in np_list:
+            assert (np.array([], dtype=n).reshape((0, 0))).dtype == n
+
 
 class TestDataFrameConstructorIndexInference:
     def test_frame_from_dict_of_series_overlapping_monthly_period_indexes(self):