DOC: add example to whats new

doc/users/next_whats_new/rcparams_dates.rst

@@ -1,11 +1,31 @@
 New rcParams for dates: set converter and whether to use interval_multiples
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-The new :rc:`dates.converter` allows toggling between
+The new :rc:`date.converter` allows toggling between
 `matplotlib.dates.DateConverter` and `matplotlib.dates.ConciseDateConverter`
 using the strings 'auto' and 'concise' respectively.
 
-The new :rc:`dates.interval_multiples` allows toggling between the dates
+The new :rc:`date.interval_multiples` allows toggling between the dates
 locator trying to pick ticks at set intervals (i.e. day 1 and 15 of the
 month), versus evenly spaced ticks that start where ever the
-timeseries starts.  
+timeseries starts:
+
+.. plot::
+    :include-source: True
+
+    import matplotlib.pyplot as plt
+    import numpy as np
+
+    dates = np.arange('2001-01-10', '2001-05-23', dtype='datetime64[D]')
+    y = np.sin(dates.astype(float) / 10)
+    fig, axs = plt.subplots(nrows=2, constrained_layout=True)
+
+    plt.rcParams['date.converter'] = 'concise'
+    plt.rcParams['date.interval_multiples'] = True
+    ax = axs[0]
+    ax.plot(dates, y)
+
+    plt.rcParams['date.converter'] = 'auto'
+    plt.rcParams['date.interval_multiples'] = False
+    ax = axs[1]
+    ax.plot(dates, y)

lib/matplotlib/dates.py

@@ -1832,7 +1832,7 @@ class DateConverter(units.ConversionInterface):
     The 'unit' tag for such data is None or a tzinfo instance.
     """
 
-    def __init__(self, interval_multiples=True):
+    def __init__(self, *, interval_multiples=True):
         self._interval_multiples = interval_multiples
         super().__init__()
 
@@ -1888,7 +1888,7 @@ class ConciseDateConverter(DateConverter):
     # docstring inherited
 
     def __init__(self, formats=None, zero_formats=None, offset_formats=None,
-                 show_offset=True, interval_multiples=True):
+                 show_offset=True, *, interval_multiples=True):
         self._formats = formats
         self._zero_formats = zero_formats
         self._offset_formats = offset_formats