On 23/07/2012 03:01, JonBL wrote: > > Using FuncFormatter with my conversion procedure has solved my problem. I did > not use the Python datetime module to generate the tickmark labels as some > of your examples suggested. Instead, my conversion procedure pulls the > required formatted date string for an x-axis ticklabel date serial number > from an Oracle database which is the source of my plotted data. > > This approach has also answered another question I had in mind - how do I > get the x= co-ordinate displayed at the bottom of the figure, to report the > formatted date rather than its serial number. > > I also had a response from Phil Elson who suggested using using > FuncFormatter as well. Many thanks to both of you for your timely responses > to my query. > > Regards, > Jon
Brilliant :) I was just about to ask how to do this!!! > > Benjamin Root-2 wrote: >> >> On Sat, Jul 21, 2012 at 10:27 PM, JonBL <jc.bl...@bigpond.net.au> wrote: >> >>> >>> I have a line plot where the x-axis values are numbers, with displayed >>> tick >>> mark values of 0, 100, 200 ... 500 - a total of 6 tick marks. These >>> values >>> represent the number of days since a certain date. I have a function >>> which >>> converts a number such as 100, to date string '23-Jun-11', which I want >>> to >>> display as the x-axis label instead of 100. >>> >>> Following the pypib example xaxis_props.py, and printing dir(label) for >>> each >>> label in the x-axis tick labels, I can see that a label object supports a >>> number of methods that might assist in changing the text of tick mark >>> labels. I was hoping to use the get_text() method to retrieve the label's >>> text (eg, 100), transform this to a date string by my function, and then >>> use >>> the set_text() method to re-assign the displayed label. >>> >>> This approach does not work for me. The get_text() method returns a >>> zero-length string (not None) for each label, and the set_text() method >>> does >>> not change the displayed tick mark values. But I can use the set_color() >>> method to change the colour of displayed values as per example >>> xaxis_props.py. >>> >>> Any suggestions on how to change the text of displayed x-axis tick marks? >>> >>> TIA, >>> Jon >>> >> >> Without example code, it would be difficult to determine what you are >> doing >> incorrectly. That being said, there is an easier solution. If you know >> the start date, do the following: >> >> from datetime import datetime, timedelta >> startdate = datetime.strptime(datestr, "%d-%m-%y) # you need to look up >> the format character for named months. >> >> xdates = np.array([startdate + timedelta(days=i) for i in xrange(501)]) >> y = np.random.random(xdates.shape) >> >> plt.plot(xdates, y) # This should work, but plot_date() definitely will >> work. >> >> Matplotlib recognizes the python datetime object and should format it for >> you. You can even control the formatting. See the following examples: >> http://matplotlib.sourceforge.net/examples/pylab_examples/date_demo_convert.html?highlight=datetime%20codex >> http://matplotlib.sourceforge.net/examples/pylab_examples/date_demo2.html?highlight=datetime%20codex >> http://matplotlib.sourceforge.net/examples/api/date_demo.html?highlight=datetime%20codex >> http://matplotlib.sourceforge.net/examples/pylab_examples/date_demo1.html?highlight=datetime%20codex >> >> >> I hope this helps! >> Ben Root >> >> ------------------------------------------------------------------------------ >> Live Security Virtual Conference >> Exclusive live event will cover all the ways today's security and >> threat landscape has changed and how IT managers can respond. Discussions >> will include endpoint security, mobile security and the latest in malware >> threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ >> _______________________________________________ >> Matplotlib-users mailing list >> Matplotlib-users@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/matplotlib-users >> >> > -- Cheers. Mark Lawrence. ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
