API: DatetimeIndex.__init__ accepts nat by str

Author: sinhrks

doc/source/v0.15.0.txt

@@ -270,6 +270,7 @@ Enhancements
 
 
 
+- ``DatetimeIndex`` can be instanciated using strings contains ``NaT`` (:issue:`7599`)
 
 
 

pandas/tseries/tests/test_timeseries.py

@@ -2159,6 +2159,15 @@ def test_constructor_coverage(self):
         from_ints = DatetimeIndex(expected.asi8)
         self.assertTrue(from_ints.equals(expected))
 
+        # string with NaT
+        strings = np.array(['2000-01-01', '2000-01-02', 'NaT'])
+        result = DatetimeIndex(strings)
+        expected = DatetimeIndex(strings.astype('O'))
+        self.assertTrue(result.equals(expected))
+
+        from_ints = DatetimeIndex(expected.asi8)
+        self.assertTrue(from_ints.equals(expected))
+
         # non-conforming
         self.assertRaises(ValueError, DatetimeIndex,
                           ['2000-01-01', '2000-01-02', '2000-01-04'],

pandas/tseries/tools.py

@@ -380,13 +380,14 @@ def parse_time_string(arg, freq=None, dayfirst=None, yearfirst=None):
     datetime, datetime/dateutil.parser._result, str
     """
     from pandas.core.config import get_option
-    from pandas.tseries.offsets import DateOffset
-    from pandas.tseries.frequencies import (_get_rule_month, _month_numbers,
-                                            _get_freq_str)
+    from pandas.tseries.frequencies import _get_rule_month, _month_numbers
 
     if not isinstance(arg, compat.string_types):
         return arg
 
+    if arg in tslib._nat_strings:
+        return tslib.NaT, tslib.NaT, ''
+
     arg = arg.upper()
 
     default = datetime(1, 1, 1).replace(hour=0, minute=0,