SF.net SVN: matplotlib: [5437] trunk/matplotlib/doc

[<jd...@us...>]

Revision: 5437
          http://matplotlib.svn.sourceforge.net/matplotlib/?rev=5437&view=rev
Author:   jdh2358
Date:     2008-06-09 10:47:43 -0700 (Mon, 09 Jun 2008)

Log Message:
-----------
added date index plot faq

Modified Paths:
--------------
    trunk/matplotlib/doc/devel/outline.rst
    trunk/matplotlib/doc/faq/howto_faq.rst
    trunk/matplotlib/doc/make.py

Modified: trunk/matplotlib/doc/devel/outline.rst
===================================================================
--- trunk/matplotlib/doc/devel/outline.rst	2008-06-09 17:47:32 UTC (rev 5436)
+++ trunk/matplotlib/doc/devel/outline.rst	2008-06-09 17:47:43 UTC (rev 5437)
@@ -22,7 +22,7 @@
 date plots                       John                 has author   ?
 working with data                John                 has author   Darren
 custom ticking                   ?                    no author    ?
-masked data                      Eric                 has author    ?
+masked data                      Eric                 has author   ?
 text                             ?                    no author    ?
 patches                          ?                    no author    ?
 legends                          ?                    no author    ?

Modified: trunk/matplotlib/doc/faq/howto_faq.rst
===================================================================
--- trunk/matplotlib/doc/faq/howto_faq.rst	2008-06-09 17:47:32 UTC (rev 5436)
+++ trunk/matplotlib/doc/faq/howto_faq.rst	2008-06-09 17:47:43 UTC (rev 5437)
@@ -91,3 +91,41 @@
 ----------------------------------
 
 TODO
+
+
+.. _date-index-plots:
+
+How do I skip dates where there is no data?
+===========================================
+
+When plotting time series, eg financial time series, one often wants
+to leave out days on which there is no data, eg weekends.  By passing
+in dates on the x-xaxis, you get large horizontal gaps on periods when
+there is not data. The solution is to pass in some proxy x-data, eg
+evenly sampled indicies, and then use a custom formatter to format
+these as dates. The example below shows how to use an 'index formatter'
+to achieve the desired plot
+
+  import numpy as np
+  import matplotlib.pyplot as plt
+  import matplotlib.mlab as mlab
+  import matplotlib.ticker as ticker
+
+  r = mlab.csv2rec('../data/aapl.csv')
+  r.sort()
+  r = r[-30:]  # get the last 30 days
+
+  N = len(r)
+  ind = np.arange(N)  # the evenly spaced plot indices
+
+  def format_date(x, pos=None):
+      thisind = np.clip(int(x+0.5), 0, N-1)
+      return r.date[thisind].strftime('%Y-%m-%d')
+
+  fig = plt.figure()
+  ax = fig.add_subplot(111)
+  ax.plot(ind, r.adj_close, 'o-')
+  ax.xaxis.set_major_formatter(ticker.FuncFormatter(format_date))
+  fig.autofmt_xdate()
+
+  plt.show()

Modified: trunk/matplotlib/doc/make.py
===================================================================
--- trunk/matplotlib/doc/make.py	2008-06-09 17:47:32 UTC (rev 5436)
+++ trunk/matplotlib/doc/make.py	2008-06-09 17:47:43 UTC (rev 5437)
@@ -14,6 +14,10 @@
         except OSError:
             pass
 
+def sf():
+    'push a copy to the sf site'
+    os.system('cd build; rsync -avz html jd...@ma...:/home/groups/m/ma/matplotlib/htdocs/doc/ -essh')
+
 def figs():
     os.system('cd users/figures/ && python make.py')
 
@@ -56,6 +60,7 @@
          'html':html,
          'latex':latex,
          'clean':clean,
+         'sf':sf,
          'all':all,
          }
 


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