WIP: attempt to fix pd.NaT plotting

Some progress on pandas-dev#9253.

Note: this did not work. I'm not quite sure why.

Author: shoyer

pandas/tseries/converter.py

@@ -26,6 +26,7 @@
 
 def register():
     units.registry[lib.Timestamp] = DatetimeConverter()
+    units.registry[lib.NaT] = DatetimeConverter()
     units.registry[Period] = PeriodConverter()
     units.registry[pydt.datetime] = DatetimeConverter()
     units.registry[pydt.date] = DatetimeConverter()
@@ -150,6 +151,8 @@ def _dt_to_float_ordinal(dt):
     """
     if isinstance(dt, (np.ndarray, Index, Series)) and com.is_datetime64_ns_dtype(dt):
         base = dates.epoch2num(dt.asi8 / 1.0E9)
+    elif dt is lib.NaT:
+        base = np.nan
     else:
         base = dates.date2num(dt)
     return base
@@ -166,7 +169,7 @@ def try_parse(values):
             except Exception:
                 return values
 
-        if isinstance(values, (datetime, pydt.date)):
+        if isinstance(values, (datetime, pydt.date)) or values is lib.NaT:
             return _dt_to_float_ordinal(values)
         elif isinstance(values, np.datetime64):
             return _dt_to_float_ordinal(lib.Timestamp(values))

pandas/tseries/tests/test_plotting.py

@@ -7,7 +7,7 @@
 from numpy.testing.decorators import slow
 from numpy.testing import assert_array_equal
 
-from pandas import Index, Series, DataFrame
+from pandas import Index, Series, DataFrame, NaT
 
 from pandas.tseries.index import date_range, bdate_range
 from pandas.tseries.offsets import DateOffset
@@ -1102,6 +1102,11 @@ def test_secondary_y_irregular_ts_xlim(self):
         self.assertEqual(left, ts_irregular.index.min().toordinal())
         self.assertEqual(right, ts_irregular.index.max().toordinal())
 
+    @slow
+    def test_plot_nat(self):
+        import matplotlib.pyplot as plt
+        plt.plot(NaT, 5)
+
 
 def _check_plot_works(f, freq=None, series=None, *args, **kwargs):
     import matplotlib.pyplot as plt