No plot window in matplotlib

You can type

import pylab
pylab.show()

or better, use ipython -pylab.

Since the use of pylab is not recommended anymore, the solution would nowadays be

import matplotlib.pyplot as plt

plt.plot([1,2,3])

plt.show()

pylab.show() works but blocks (you need to close the window).

A much more convenient solution is to do pylab.ion() (interactive mode on) when you start: all (the pylab equivalents of) pyplot.* commands display their plot immediately. More information on the interactive mode can be found on the official web site.

I also second using the even more convenient ipython -pylab (--pylab, in newer versions), which allows you to skip the from … import … part (%pylab works, too, in newer IPython versions).

Try this:

import matplotlib
matplotlib.use('TkAgg') 

BEFORE import pylab

Any errors show up? This might an issue of not having set the backend. You can set it from the Python interpreter or from a config file (.matplotlib/matplotlibrc) in you home directory.

To set the backend in code you can do

import matplotlib
matplotlib.use('Agg')

where 'Agg' is the name of the backend. Which backends are present depend on your installation and OS.

http://matplotlib.sourceforge.net/faq/installing_faq.html#backends

http://matplotlib.org/users/customizing.html

Modern IPython uses the "--matplotlib" argument with an optional backend parameter. It defaults to "auto", which is usually good enough on Mac and Windows. I haven't tested it on Ubuntu or any other Linux distribution, but I would expect it to work.

ipython --matplotlib

If you are user of Anaconda and Spyder then best solution for you is that :

Tools --> Preferences --> Ipython console --> Graphic Section

Then in the Support for graphics (Matplotlib) section:

select two avaliable options

and in the Graphics Backend:

select Automatic