REGR: pd.to_hdf(..., dropna=True) not dropping missing rows

doc/source/whatsnew/v1.2.0.rst

@@ -492,6 +492,7 @@ I/O
 - Bug in output rendering of complex numbers showing too many trailing zeros (:issue:`36799`)
 - Bug in :class:`HDFStore` threw a ``TypeError`` when exporting an empty :class:`DataFrame` with ``datetime64[ns, tz]`` dtypes with a fixed HDF5 store (:issue:`20594`)
 - Bug in :class:`HDFStore` was dropping timezone information when exporting :class:`Series` with ``datetime64[ns, tz]`` dtypes with a fixed HDF5 store (:issue:`20594`)
+- Bug in :meth:`DataFrame.to_hdf` was not dropping missing rows with ``dropna=True`` (:issue:`35719`)
 
 Plotting
 ^^^^^^^^

pandas/io/pytables.py

@@ -268,6 +268,7 @@ def to_hdf(
             data_columns=data_columns,
             errors=errors,
             encoding=encoding,
+            dropna=dropna,
         )
 
     path_or_buf = stringify_path(path_or_buf)
@@ -1051,6 +1052,7 @@ def put(
         encoding=None,
         errors: str = "strict",
         track_times: bool = True,
+        dropna: bool = False,
     ):
         """
         Store object in HDFStore.
@@ -1100,6 +1102,7 @@ def put(
             encoding=encoding,
             errors=errors,
             track_times=track_times,
+            dropna=dropna,
         )
 
     def remove(self, key: str, where=None, start=None, stop=None):

pandas/tests/io/pytables/test_store.py

@@ -1253,17 +1253,32 @@ def test_append_all_nans(self, setup_path):
             store.append("df2", df[10:], dropna=False)
             tm.assert_frame_equal(store["df2"], df)
 
-        # Test to make sure defaults are to not drop.
-        # Corresponding to Issue 9382
+    def test_store_dropna(self, setup_path):
         df_with_missing = DataFrame(
-            {"col1": [0, np.nan, 2], "col2": [1, np.nan, np.nan]}
+            {"col1": [0.0, np.nan, 2.0], "col2": [1.0, np.nan, np.nan]},
+            index=list("abc"),
         )
+        df_without_missing = DataFrame(
+            {"col1": [0.0, 2.0], "col2": [1.0, np.nan]}, index=list("ac")
+        )
+
+        # # Test to make sure defaults are to not drop.
+        # # Corresponding to Issue 9382
+        with ensure_clean_path(setup_path) as path:
+            df_with_missing.to_hdf(path, "df", format="table")
+            reloaded = read_hdf(path, "df")
+            tm.assert_frame_equal(df_with_missing, reloaded)
 
         with ensure_clean_path(setup_path) as path:
-            df_with_missing.to_hdf(path, "df_with_missing", format="table")
-            reloaded = read_hdf(path, "df_with_missing")
+            df_with_missing.to_hdf(path, "df", format="table", dropna=False)
+            reloaded = read_hdf(path, "df")
             tm.assert_frame_equal(df_with_missing, reloaded)
 
+        with ensure_clean_path(setup_path) as path:
+            df_with_missing.to_hdf(path, "df", format="table", dropna=True)
+            reloaded = read_hdf(path, "df")
+            tm.assert_frame_equal(df_without_missing, reloaded)
+
     def test_read_missing_key_close_store(self, setup_path):
         # GH 25766
         with ensure_clean_path(setup_path) as path: