REF: privatize get_datevalue

Author: jbrockmendel

pandas/plotting/_matplotlib/converter.py

@@ -252,21 +252,21 @@ def _convert_1d(values, freq):
                 or is_integer(values)
                 or is_float(values)
             ):
-                return get_datevalue(values, freq)
+                return _get_datevalue(values, freq)
             elif isinstance(values, PeriodIndex):
                 return values.asfreq(freq).asi8
             elif isinstance(values, Index):
-                return values.map(lambda x: get_datevalue(x, freq))
+                return values.map(lambda x: _get_datevalue(x, freq))
             elif lib.infer_dtype(values, skipna=False) == "period":
                 # https://github.com/pandas-dev/pandas/issues/24304
                 # convert ndarray[period] -> PeriodIndex
                 return PeriodIndex(values, freq=freq).asi8
             elif isinstance(values, (list, tuple, np.ndarray, Index)):
-                return [get_datevalue(x, freq) for x in values]
+                return [_get_datevalue(x, freq) for x in values]
         return values
 
 
-def get_datevalue(date, freq):
+def _get_datevalue(date, freq):
     if isinstance(date, Period):
         return date.asfreq(freq).ordinal
     elif isinstance(date, (str, datetime, pydt.date, pydt.time, np.datetime64)):

pandas/tests/plotting/test_datetimelike.py

@@ -165,12 +165,13 @@ def test_high_freq(self, freq):
         _check_plot_works(ser.plot, ax=ax)
 
     def test_get_datevalue(self):
-        assert conv.get_datevalue(None, "D") is None
-        assert conv.get_datevalue(1987, "Y") == 1987
+        assert conv._get_datevalue(None, "D") is None
+        assert conv._get_datevalue(1987, "Y") == 1987
         assert (
-            conv.get_datevalue(Period(1987, "Y"), "M") == Period("1987-12", "M").ordinal
+            conv._get_datevalue(Period(1987, "Y"), "M")
+            == Period("1987-12", "M").ordinal
         )
-        assert conv.get_datevalue("1/1/1987", "D") == Period("1987-1-1", "D").ordinal
+        assert conv._get_datevalue("1/1/1987", "D") == Period("1987-1-1", "D").ordinal
 
     @pytest.mark.parametrize(
         "freq, expected_string",