Saving plots without displaying them?
Richard Stanton
Sometimes I want to create and save a large number of plots, and it would be very convenient to be able to create and save them on disk without first displaying them on the screen. Is there a way to do this?
Thanks for any suggestions.
Richard Stanton
Adam Hughes
Look at matplotlibs savefig function. You would call savefig then plt.clear or whatever the clear function is. Sorry responding from phone
--
Yaroslav Halchenko
backend to non-interactive one (e.g. Agg) first and then use savefig ;)
see
http://matplotlib.org/faq/howto_faq.html#generate-images-without-having-a-window-appear
Yaroslav O. Halchenko
Postdoctoral Fellow, Department of Psychological and Brain Sciences
Dartmouth College, 419 Moore Hall, Hinman Box 6207, Hanover, NH 03755
Phone: +1 (603) 646-9834 Fax: +1 (603) 646-1419
WWW: http://www.linkedin.com/in/yarik
Richard Stanton
> I guess should be as with any module using matplotlib -- just set
> backend to non-interactive one (e.g. Agg) first and then use savefig ;)
> see
> http://matplotlib.org/faq/howto_faq.html#generate-images-without-having-a-window-appear
matplotlib.use('Agg'),
even right at the beginning of the notebook, I get the warning
UserWarning: This call to matplotlib.use() has no effect
because the the backend has already been chosen;
matplotlib.use() must be called *before* pylab, matplotlib.pyplot,
or matplotlib.backends is imported for the first time.
and the plot command continues to display on the screen.
Goyo
Eraldo Pomponi
Dear Richard,
Il giorno 19/gen/2013 09:07, "Richard Stanton" <sta...@haas.berkeley.edu> ha scritto:
>
> Yaroslav Halchenko <yarik...@gmail.com> Jan 17 10:59PM -0500
>
> > I guess should be as with any module using matplotlib -- just set
> > backend to non-interactive one (e.g. Agg) first and then use savefig ;)
> > see
> > http://matplotlib.org/faq/howto_faq.html#generate-images-without-having-a-window-appear
>
> Thanks very much for the suggestion. The problem is that I'm trying to do this in an IPython notebook, and whenever I execute a plot command, the graph immediately appears on the screen. I can save it as well, using savefig, but it would be much faster if it wasn't displayed at all. I tried following the advice given in the link above, but when I try to execute the command
>
> matplotlib.use('Agg'),
>
> even right at the beginning of the notebook, I get the warning
>
> UserWarning: This call to matplotlib.use() has no effect
> because the the backend has already been chosen;
Import matplotlib explicitly ... Do not use --pylab when starting ipython notebook.
Im this way you should be able to fix the matplotlib backend as you wish.
HTH,
Eraldo
Richard Stanton
> That's because you are starting the notebook in pylab mode. Don't do that
> if you want to change the matplotlib backend in the notebook.
> Import matplotlib explicitly ... Do not use --pylab when starting ipython
> notebook.
Now the bonus question...
Is there any way to toggle the plotting behavior *within a single notebook*? Here's an example of what I'd like to do:
1) In one cell, plot a graph and have it displayed on the screen (within the notebook - not in a separate window)
2) In a later cell in the same notebook, have a loop where I generate and save multiple graphs. For this cell, to save time I don't want the graphs displayed on the screen as they're generated.
