added autofmt for date plots

jdh2358 · jdh2358 · commit e927e25e0289 · 2007-04-17T14:02:52.000Z
svn path=/trunk/matplotlib/; revision=3239
diff --git a/CHANGELOG b/CHANGELOG
@@ -1,3 +1,7 @@
+2007-04-16 Added autofmt_xdate to handle adjusting the bottom and
+           rotating the tick labels for date plots when the ticks
+           often overlap
+
 2007-04-09 Beginnings of usetex support for pdf backend. -JKS
 
 2007-04-07 Fixed legend/LineCollection bug. Added label support
diff --git a/examples/load_converter.py b/examples/load_converter.py
@@ -1,10 +1,14 @@
-from pylab import figure, show, datestr2num, load
+from matplotlib.dates import strpdate2num
+from matplotlib.mlab import load
+from pylab import figure, show
+
 dates, closes = load(
     'data/msft.csv', delimiter=',',
-    converters={0:datestr2num}, skiprows=1, usecols=(0,2),
-    unpack=True)
+    converters={0:strpdate2num('%d-%b-%y')},
+    skiprows=1, usecols=(0,2), unpack=True)
 
 fig = figure()
 ax = fig.add_subplot(111)
-ax.plot_date(dates, closes)
+ax.plot_date(dates, closes, '-')
+fig.autofmt_xdate()
 show()
diff --git a/lib/matplotlib/dates.py b/lib/matplotlib/dates.py
@@ -167,6 +167,22 @@ def _from_ordinalf(x, tz=None):
 
     return dt
 
+class strpdate2num:
+    """
+    Use this class to parse date strings to matplotlib datenums when
+    you know the date format string of the date you are parsing.  See
+    examples/load_demo.py
+    """
+    def __init__(self, fmt):
+        """ fmt: any valid strptime format is supported """
+        self.fmt = fmt
+
+    def __call__(self, s):
+        """s : string to be converted
+           return value: a date2num float
+        """
+        return date2num(datetime.datetime(*time.strptime(s, self.fmt)[:6]))
+    
 def datestr2num(d):
     """
     Convert a date string to a datenum using dateutil.parser.parse
diff --git a/lib/matplotlib/figure.py b/lib/matplotlib/figure.py
@@ -158,6 +158,33 @@ def __init__(self,
 
         self._cachedRenderer = None
 
+    def autofmt_xdate(self, bottom=0.2, rotation=30, ha='right'):
+        """
+        A common use case is a number of subplots with shared xaxes
+        where the x-axis is date data.  The ticklabels are often
+        long,and it helps to rotate them on the bottom subplot and
+        turn them off on other subplots.  This function will raise a
+        RuntimeError if any of the Axes are not Subplots.
+
+        bottom : the bottom of the subplots for subplots_adjust
+        rotation: the rotation of the xtick labels
+        ha : the horizontal alignment of the xticklabels
+
+        
+        """
+
+        for ax in self.get_axes():
+            if not hasattr(ax, 'is_last_row'):
+                raise RuntimeError('Axes must be subplot instances; found %s'%type(ax))
+            if ax.is_last_row():
+                for label in ax.get_xticklabels():
+                    label.set_ha(ha)
+                    label.set_rotation(rotation)                
+            else:
+                for label in ax.get_xticklabels():
+                    label.set_visible(False)
+        self.subplots_adjust(bottom=bottom)
+        
     def get_children(self):
         'get a list of artists contained in the figure'
         children = [self.figurePatch]
diff --git a/lib/matplotlib/pylab.py b/lib/matplotlib/pylab.py
@@ -236,7 +236,7 @@
 # eg a bad pytz install.  I don't want to break all of matplotlib for
 # date support
 try:
-    from dates import date2num, num2date, datestr2num, drange,\
+    from dates import date2num, num2date, datestr2num, strpdate2num, drange,\
             epoch2num, num2epoch, mx2num,\
             DateFormatter, IndexDateFormatter, DateLocator,\
             RRuleLocator, YearLocator, MonthLocator, WeekdayLocator,\
