Make default for convert_datetime64=None and adjust tests

doc/source/whatsnew/v0.23.0.txt

@@ -842,7 +842,7 @@ Deprecations
 - ``pandas.tseries.plotting.tsplot`` is deprecated. Use :func:`Series.plot` instead (:issue:`18627`)
 - ``Index.summary()`` is deprecated and will be removed in a future version (:issue:`18217`)
 - ``NDFrame.get_ftype_counts()`` is deprecated and will be removed in a future version (:issue:`18243`)
-- The ``convert_datetime64`` parameter in :func:`DataFrame.to_records` has been deprecated and will be removed in a future version. The NumPy bug motivating this parameter has been resolved (:issue:`18160`).
+- The ``convert_datetime64`` parameter in :func:`DataFrame.to_records` has been deprecated and will be removed in a future version. The NumPy bug motivating this parameter has been resolved. The default value for this parameter has also changed from ``True`` to ``None`` (:issue:`18160`).
 
 .. _whatsnew_0230.prior_deprecations:
 

pandas/core/frame.py

@@ -1311,7 +1311,7 @@ def from_records(cls, data, index=None, exclude=None, columns=None,
 
         return cls(mgr)
 
-    def to_records(self, index=True, convert_datetime64=False):
+    def to_records(self, index=True, convert_datetime64=None):
         """
         Convert DataFrame to a NumPy record array.
 
@@ -1322,7 +1322,7 @@ def to_records(self, index=True, convert_datetime64=False):
         ----------
         index : boolean, default True
             Include index in resulting record array, stored in 'index' field.
-        convert_datetime64 : boolean, default False
+        convert_datetime64 : boolean, default None
             .. deprecated:: 0.23.0
 
             Whether to convert the index to datetime.datetime if it is a
@@ -1379,7 +1379,7 @@ def to_records(self, index=True, convert_datetime64=False):
                   dtype=[('index', '<M8[ns]'), ('A', '<i8'), ('B', '<f8')])
         """
 
-        if convert_datetime64:
+        if convert_datetime64 is not None:
             warnings.warn("The 'convert_datetime64' parameter is "
                           "deprecated and will be removed in a future "
                           "version",

pandas/tests/frame/test_convert_to.py

@@ -80,17 +80,24 @@ def test_to_records_dt64(self):
                         ["four", "five", "six"]],
                        index=date_range("2012-01-01", "2012-01-02"))
 
-        # convert_datetime64 defaults to False if not passed
-        expected = df.index.values[0]
-        result = df.to_records()['index'][0]
-        assert expected == result
+        # convert_datetime64 defaults to None
+        expected = df.index.values
+        result = df.to_records()['index']
+        tm.assert_numpy_array_equal(expected, result)
+
+        # check for FutureWarning if convert_datetime64=False is passed
+        with tm.assert_produces_warning(FutureWarning):
+            expected = df.index.values
+            result = df.to_records(convert_datetime64=False)['index']
+            tm.assert_numpy_array_equal(expected, result)
 
         # check for FutureWarning if convert_datetime64=True is passed
         with tm.assert_produces_warning(FutureWarning):
             expected = df.index[0]
             result = df.to_records(convert_datetime64=True)['index'][0]
             assert expected == result
 
+
     def test_to_records_with_multindex(self):
         # GH3189
         index = [['bar', 'bar', 'baz', 'baz', 'foo', 'foo', 'qux', 'qux'],