Matplotlib 3.3 compatibility fixups (#35393)

ci/deps/azure-37-locale.yaml

@@ -18,7 +18,7 @@ dependencies:
   - ipython
   - jinja2
   - lxml
-  - matplotlib <3.3.0
+  - matplotlib>=3.3.0
   - moto
   - nomkl
   - numexpr

doc/source/whatsnew/v1.1.0.rst

@@ -274,6 +274,7 @@ change, as ``fsspec`` will still bring in the same packages as before.
 Other enhancements
 ^^^^^^^^^^^^^^^^^^
 
+- Compatibility with matplotlib 3.3.0 (:issue:`34850`)
 - :meth:`IntegerArray.astype` now supports ``datetime64`` dtype (:issue:`32538`)
 - :class:`IntegerArray` now implements the ``sum`` operation (:issue:`33172`)
 - Added :class:`pandas.errors.InvalidIndexError` (:issue:`34570`).

pandas/plotting/_matplotlib/boxplot.py

@@ -299,6 +299,11 @@ def plot_group(keys, values, ax):
         if fontsize is not None:
             ax.tick_params(axis="both", labelsize=fontsize)
         if kwds.get("vert", 1):
+            ticks = ax.get_xticks()
+            if len(ticks) != len(keys):
+                i, remainder = divmod(len(ticks), len(keys))
+                assert remainder == 0, remainder
+                keys *= i
             ax.set_xticklabels(keys, rotation=rot)
         else:
             ax.set_yticklabels(keys, rotation=rot)

pandas/plotting/_matplotlib/compat.py

@@ -21,3 +21,4 @@ def inner():
 _mpl_ge_3_0_0 = _mpl_version("3.0.0", operator.ge)
 _mpl_ge_3_1_0 = _mpl_version("3.1.0", operator.ge)
 _mpl_ge_3_2_0 = _mpl_version("3.2.0", operator.ge)
+_mpl_ge_3_3_0 = _mpl_version("3.3.0", operator.ge)

pandas/plotting/_matplotlib/converter.py

@@ -16,7 +16,6 @@
 from pandas._libs.tslibs.offsets import BaseOffset
 
 from pandas.core.dtypes.common import (
-    is_datetime64_ns_dtype,
     is_float,
     is_float_dtype,
     is_integer,
@@ -246,19 +245,6 @@ def get_datevalue(date, freq):
     raise ValueError(f"Unrecognizable date '{date}'")
 
 
-def _dt_to_float_ordinal(dt):
-    """
-    Convert :mod:`datetime` to the Gregorian date as UTC float days,
-    preserving hours, minutes, seconds and microseconds.  Return value
-    is a :func:`float`.
-    """
-    if isinstance(dt, (np.ndarray, Index, Series)) and is_datetime64_ns_dtype(dt):
-        base = dates.epoch2num(dt.asi8 / 1.0e9)
-    else:
-        base = dates.date2num(dt)
-    return base
-
-
 # Datetime Conversion
 class DatetimeConverter(dates.DateConverter):
     @staticmethod
@@ -274,15 +260,11 @@ def convert(values, unit, axis):
     def _convert_1d(values, unit, axis):
         def try_parse(values):
             try:
-                return _dt_to_float_ordinal(tools.to_datetime(values))
+                return dates.date2num(tools.to_datetime(values))
             except Exception:
                 return values
 
-        if isinstance(values, (datetime, pydt.date)):
-            return _dt_to_float_ordinal(values)
-        elif isinstance(values, np.datetime64):
-            return _dt_to_float_ordinal(Timestamp(values))
-        elif isinstance(values, pydt.time):
+        if isinstance(values, (datetime, pydt.date, np.datetime64, pydt.time)):
             return dates.date2num(values)
         elif is_integer(values) or is_float(values):
             return values
@@ -303,12 +285,10 @@ def try_parse(values):
 
             try:
                 values = tools.to_datetime(values)
-                if isinstance(values, Index):
-                    values = _dt_to_float_ordinal(values)
-                else:
-                    values = [_dt_to_float_ordinal(x) for x in values]
             except Exception:
-                values = _dt_to_float_ordinal(values)
+                pass
+
+            values = dates.date2num(values)
 
         return values
 
@@ -411,8 +391,8 @@ def __call__(self):
         interval = self._get_interval()
         freq = f"{interval}L"
         tz = self.tz.tzname(None)
-        st = _from_ordinal(dates.date2num(dmin))  # strip tz
-        ed = _from_ordinal(dates.date2num(dmax))
+        st = dmin.replace(tzinfo=None)
+        ed = dmin.replace(tzinfo=None)
         all_dates = date_range(start=st, end=ed, freq=freq, tz=tz).astype(object)
 
         try:

pandas/tests/plotting/test_converter.py

@@ -27,6 +27,7 @@
     pass
 
 pytest.importorskip("matplotlib.pyplot")
+dates = pytest.importorskip("matplotlib.dates")
 
 
 def test_registry_mpl_resets():
@@ -146,7 +147,7 @@ def test_convert_accepts_unicode(self):
 
     def test_conversion(self):
         rs = self.dtc.convert(["2012-1-1"], None, None)[0]
-        xp = datetime(2012, 1, 1).toordinal()
+        xp = dates.date2num(datetime(2012, 1, 1))
         assert rs == xp
 
         rs = self.dtc.convert("2012-1-1", None, None)
@@ -155,9 +156,6 @@ def test_conversion(self):
         rs = self.dtc.convert(date(2012, 1, 1), None, None)
         assert rs == xp
 
-        rs = self.dtc.convert(datetime(2012, 1, 1).toordinal(), None, None)
-        assert rs == xp
-
         rs = self.dtc.convert("2012-1-1", None, None)
         assert rs == xp
 

pandas/tests/plotting/test_datetimelike.py

@@ -331,7 +331,7 @@ def test_freq_with_no_period_alias(self):
         bts = tm.makeTimeSeries(5).asfreq(freq)
         _, ax = self.plt.subplots()
         bts.plot(ax=ax)
-        assert ax.get_lines()[0].get_xydata()[0, 0] == bts.index[0].toordinal()
+
         idx = ax.get_lines()[0].get_xdata()
         msg = "freq not specified and cannot be inferred"
         with pytest.raises(ValueError, match=msg):
@@ -1279,6 +1279,8 @@ def test_mpl_nopandas(self):
     @pytest.mark.slow
     def test_irregular_ts_shared_ax_xlim(self):
         # GH 2960
+        from pandas.plotting._matplotlib.converter import DatetimeConverter
+
         ts = tm.makeTimeSeries()[:20]
         ts_irregular = ts[[1, 4, 5, 6, 8, 9, 10, 12, 13, 14, 15, 17, 18]]
 
@@ -1289,8 +1291,8 @@ def test_irregular_ts_shared_ax_xlim(self):
 
         # check that axis limits are correct
         left, right = ax.get_xlim()
-        assert left <= ts_irregular.index.min().toordinal()
-        assert right >= ts_irregular.index.max().toordinal()
+        assert left <= DatetimeConverter.convert(ts_irregular.index.min(), "", ax)
+        assert right >= DatetimeConverter.convert(ts_irregular.index.max(), "", ax)
 
     @pytest.mark.slow
     def test_secondary_y_non_ts_xlim(self):
@@ -1345,6 +1347,8 @@ def test_secondary_y_mixed_freq_ts_xlim(self):
     @pytest.mark.slow
     def test_secondary_y_irregular_ts_xlim(self):
         # GH 3490 - irregular-timeseries with secondary y
+        from pandas.plotting._matplotlib.converter import DatetimeConverter
+
         ts = tm.makeTimeSeries()[:20]
         ts_irregular = ts[[1, 4, 5, 6, 8, 9, 10, 12, 13, 14, 15, 17, 18]]
 
@@ -1356,8 +1360,8 @@ def test_secondary_y_irregular_ts_xlim(self):
         ts_irregular[:5].plot(ax=ax)
 
         left, right = ax.get_xlim()
-        assert left <= ts_irregular.index.min().toordinal()
-        assert right >= ts_irregular.index.max().toordinal()
+        assert left <= DatetimeConverter.convert(ts_irregular.index.min(), "", ax)
+        assert right >= DatetimeConverter.convert(ts_irregular.index.max(), "", ax)
 
     def test_plot_outofbounds_datetime(self):
         # 2579 - checking this does not raise

pandas/tests/plotting/test_frame.py

@@ -1563,6 +1563,7 @@ def test_boxplot(self):
             ax.xaxis.get_ticklocs(), np.arange(1, len(numeric_cols) + 1)
         )
         assert len(ax.lines) == self.bp_n_objects * len(numeric_cols)
+        tm.close()
 
         axes = series.plot.box(rot=40)
         self._check_ticks_props(axes, xrot=40, yrot=0)

pandas/tests/plotting/test_series.py

@@ -274,12 +274,14 @@ def test_rotation(self):
         self._check_ticks_props(axes, xrot=30)
 
     def test_irregular_datetime(self):
+        from pandas.plotting._matplotlib.converter import DatetimeConverter
+
         rng = date_range("1/1/2000", "3/1/2000")
         rng = rng[[0, 1, 2, 3, 5, 9, 10, 11, 12]]
         ser = Series(randn(len(rng)), rng)
         _, ax = self.plt.subplots()
         ax = ser.plot(ax=ax)
-        xp = datetime(1999, 1, 1).toordinal()
+        xp = DatetimeConverter.convert(datetime(1999, 1, 1), "", ax)
         ax.set_xlim("1/1/1999", "1/1/2001")
         assert xp == ax.get_xlim()[0]
 
@@ -684,11 +686,13 @@ def test_kind_both_ways(self):
         kinds = (
             plotting.PlotAccessor._common_kinds + plotting.PlotAccessor._series_kinds
         )
-        _, ax = self.plt.subplots()
         for kind in kinds:
-
+            _, ax = self.plt.subplots()
             s.plot(kind=kind, ax=ax)
+            self.plt.close()
+            _, ax = self.plt.subplots()
             getattr(s.plot, kind)()
+            self.plt.close()
 
     @pytest.mark.slow
     def test_invalid_plot_data(self):