Merge pull request #23188 from jklymak/mnt-new-default-dates

greglucas · web-flow · commit 028f07c869c4 · 2022-06-03T07:19:51.000-06:00
Mnt new default dates
diff --git a/doc/api/next_api_changes/behavior/23188-JMK.rst b/doc/api/next_api_changes/behavior/23188-JMK.rst
@@ -0,0 +1,9 @@
+Default date limits changed to 1970-01-01 to 1970-01-02
+-------------------------------------------------------
+
+Previously the default limits for an empty axis set up for dates
+(`.Axis.axis_date`) was 2000-01-01 to 2010-01-01.  This has been
+changed to 1970-01-01 to 1970-01-02.  With the default epoch, this
+makes the numeric limit for date axes the same as for other axes
+(0.0-1.0), and users are less likely to set a locator with far too
+many ticks.
diff --git a/lib/matplotlib/dates.py b/lib/matplotlib/dates.py
@@ -1157,9 +1157,9 @@ def nonsingular(self, vmin, vmax):
         if it is too close to being singular (i.e. a range of ~0).
         """
         if not np.isfinite(vmin) or not np.isfinite(vmax):
-            # Except if there is no data, then use 2000-2010 as default.
-            return (date2num(datetime.date(2000, 1, 1)),
-                    date2num(datetime.date(2010, 1, 1)))
+            # Except if there is no data, then use 1970 as default.
+            return (date2num(datetime.date(1970, 1, 1)),
+                    date2num(datetime.date(1970, 1, 2)))
         if vmax < vmin:
             vmin, vmax = vmax, vmin
         unit = self._get_unit()
@@ -1362,9 +1362,9 @@ def nonsingular(self, vmin, vmax):
         # whatever is thrown at us, we can scale the unit.
         # But default nonsingular date plots at an ~4 year period.
         if not np.isfinite(vmin) or not np.isfinite(vmax):
-            # Except if there is no data, then use 2000-2010 as default.
-            return (date2num(datetime.date(2000, 1, 1)),
-                    date2num(datetime.date(2010, 1, 1)))
+            # Except if there is no data, then use 1970 as default.
+            return (date2num(datetime.date(1970, 1, 1)),
+                    date2num(datetime.date(1970, 1, 2)))
         if vmax < vmin:
             vmin, vmax = vmax, vmin
         if vmin == vmax:
@@ -1850,8 +1850,8 @@ def axisinfo(self, unit, axis):
         majloc = AutoDateLocator(tz=tz,
                                  interval_multiples=self._interval_multiples)
         majfmt = AutoDateFormatter(majloc, tz=tz)
-        datemin = datetime.date(2000, 1, 1)
-        datemax = datetime.date(2010, 1, 1)
+        datemin = datetime.date(1970, 1, 1)
+        datemax = datetime.date(1970, 1, 2)
 
         return units.AxisInfo(majloc=majloc, majfmt=majfmt, label='',
                               default_limits=(datemin, datemax))
@@ -1907,8 +1907,8 @@ def axisinfo(self, unit, axis):
                                       zero_formats=self._zero_formats,
                                       offset_formats=self._offset_formats,
                                       show_offset=self._show_offset)
-        datemin = datetime.date(2000, 1, 1)
-        datemax = datetime.date(2010, 1, 1)
+        datemin = datetime.date(1970, 1, 1)
+        datemax = datetime.date(1970, 1, 2)
         return units.AxisInfo(majloc=majloc, majfmt=majfmt, label='',
                               default_limits=(datemin, datemax))
 
diff --git a/lib/matplotlib/tests/test_axes.py b/lib/matplotlib/tests/test_axes.py
@@ -7081,19 +7081,6 @@ def test_axis_extent_arg2():
     assert (ymin, ymax) == ax.get_ylim()
 
 
-def test_datetime_masked():
-    # make sure that all-masked data falls back to the viewlim
-    # set in convert.axisinfo....
-    x = np.array([datetime.datetime(2017, 1, n) for n in range(1, 6)])
-    y = np.array([1, 2, 3, 4, 5])
-    m = np.ma.masked_greater(y, 0)
-
-    fig, ax = plt.subplots()
-    ax.plot(x, m)
-    dt = mdates.date2num(np.datetime64('0000-12-31'))
-    assert ax.get_xlim() == (730120.0 + dt, 733773.0 + dt)
-
-
 def test_hist_auto_bins():
     _, bins, _ = plt.hist([[1, 2, 3], [3, 4, 5, 6]], bins='auto')
     assert bins[0] <= 1
diff --git a/lib/matplotlib/tests/test_dates.py b/lib/matplotlib/tests/test_dates.py
@@ -77,17 +77,17 @@ def test_date_empty():
     ax.xaxis_date()
     fig.draw_without_rendering()
     np.testing.assert_allclose(ax.get_xlim(),
-                               [mdates.date2num(np.datetime64('2000-01-01')),
-                                mdates.date2num(np.datetime64('2010-01-01'))])
+                               [mdates.date2num(np.datetime64('1970-01-01')),
+                                mdates.date2num(np.datetime64('1970-01-02'))])
 
     mdates._reset_epoch_test_example()
     mdates.set_epoch('0000-12-31')
     fig, ax = plt.subplots()
     ax.xaxis_date()
     fig.draw_without_rendering()
     np.testing.assert_allclose(ax.get_xlim(),
-                               [mdates.date2num(np.datetime64('2000-01-01')),
-                                mdates.date2num(np.datetime64('2010-01-01'))])
+                               [mdates.date2num(np.datetime64('1970-01-01')),
+                                mdates.date2num(np.datetime64('1970-01-02'))])
     mdates._reset_epoch_test_example()
 
 
@@ -1235,7 +1235,7 @@ def test_julian2num():
 def test_DateLocator():
     locator = mdates.DateLocator()
     # Test nonsingular
-    assert locator.nonsingular(0, np.inf) == (10957.0, 14610.0)
+    assert locator.nonsingular(0, np.inf) == (0, 1)
     assert locator.nonsingular(0, 1) == (0, 1)
     assert locator.nonsingular(1, 0) == (0, 1)
     assert locator.nonsingular(0, 0) == (-2, 2)
@@ -1328,3 +1328,15 @@ def test_usetex_newline():
     fig, ax = plt.subplots()
     ax.xaxis.set_major_formatter(mdates.DateFormatter('%d/%m\n%Y'))
     fig.canvas.draw()
+
+
+def test_datetime_masked():
+    # make sure that all-masked data falls back to the viewlim
+    # set in convert.axisinfo....
+    x = np.array([datetime.datetime(2017, 1, n) for n in range(1, 6)])
+    y = np.array([1, 2, 3, 4, 5])
+    m = np.ma.masked_greater(y, 0)
+
+    fig, ax = plt.subplots()
+    ax.plot(x, m)
+    assert ax.get_xlim() == (0, 1)
