@@ -19,6 +19,7 @@ Fixed regressions

- Enforced reversion of ``color`` as an alias for ``c`` and ``size`` as an alias for ``s`` in function :meth:`DataFrame.plot.scatter` (:issue:`49732`)

- Fixed regression in :meth:`SeriesGroupBy.apply` setting a ``name`` attribute on the result if the result was a :class:`DataFrame` (:issue:`49907`)

- Fixed performance regression in setting with the :meth:`~DataFrame.at` indexer (:issue:`49771`)

- Fixed regression in :func:`to_datetime` raising ``ValueError`` when parsing array of ``float`` containing ``np.nan`` (:issue:`50237`)

-

.. ---------------------------------------------------------------------------

@@ -42,7 +42,11 @@ from pandas._libs.tslibs.np_datetime cimport (

pydatetime_to_dt64,

)

from pandas._libs.tslibs.timestamps cimport _Timestamp

from pandas._libs.util cimport is_datetime64_object

from pandas._libs.util cimport (

is_datetime64_object,

is_float_object,

is_integer_object,

)

cnp.import_array()

@@ -185,6 +189,12 @@ def array_strptime(

elif is_datetime64_object(val):

iresult[i] = get_datetime64_nanos(val, NPY_FR_ns)

continue

elif (

(is_integer_object(val) or is_float_object(val))

and (val != val or val == NPY_NAT)

):

iresult[i] = NPY_NAT

continue

else:

val = str(val)

@@ -135,6 +135,17 @@ def test_to_datetime_format_YYYYMMDD_with_nat(self, cache):

result = to_datetime(ser2, format="%Y%m%d", cache=cache)

tm.assert_series_equal(result, expected)

def test_to_datetime_format_YYYYMM_with_nat(self, cache):

# https://github.com/pandas-dev/pandas/issues/50237

ser = Series([198012, 198012] + [198101] * 5)

expected = Series(

[Timestamp("19801201"), Timestamp("19801201")] + [Timestamp("19810101")] * 5

)

expected[2] = np.nan

ser[2] = np.nan

result = to_datetime(ser, format="%Y%m", cache=cache)

tm.assert_series_equal(result, expected)

def test_to_datetime_format_YYYYMMDD_ignore(self, cache):

# coercion

# GH 7930