[IPython-dev] A request for help reviewing/testing a branch

John Hunter jdh2358 at gmail.com
Sat Jan 9 23:12:03 EST 2010

On Sat, Jan 9, 2010 at 9:57 PM, Fernando Perez <fperez.net at gmail.com> wrote:
> On Sat, Jan 9, 2010 at 7:53 PM, John Hunter <jdh2358 at gmail.com> wrote:
>> OK, that worked.  The following worked for me using svn mpl and your
>> ipy branch (line 6 generated a plot)-- nice work!
> Great, thanks!  This is on ubuntu, right?

Yes Karmic (9.10)

>> NameError: name 'pylab' is not defined
> BTW, since it's a magic, typing
> pylab?

> will give you info (help doesn't know anything about magics).

Ahh that is good to know.  I wasn't aware that "help" in ipython did
not have the extra functionality of "?" and was wondering why the
magic "pylab" had no docs before loaded....  Thanks for the

I was also able to test this with the default ubuntu 9.10 mpl and it
worked fine.  Backend switching does not appear to work with "%pylab
qt" and then "%pylab wx" or "%pylab tk" but I had read in a previous
thread that there should be some limited support for backend
switching....  What is the status here?

msierig at pinchiepie:~$ PYTHONPATH=~/dev/lib/python2.6/site-packages/
Python 2.6.4 (r264:75706, Dec  7 2009, 18:45:15)
Type "copyright", "credits" or "license" for more information.

IPython 0.11.bzr.r1219 -- An enhanced Interactive Python.
?         -> Introduction and overview of IPython's features.
%quickref -> Quick reference.
help      -> Python's own help system.
object?   -> Details about 'object'. ?object also works, ?? prints more.

In [1]: %pylab qt

Welcome to pylab, a matplotlib-based Python environment [backend: Qt4Agg].
For more information, type 'help(pylab)'.

In [2]: plot([1,2,3])
Out[2]: [<matplotlib.lines.Line2D object at 0xab4d0cc>]

In [3]: %pylab tk
/usr/lib/pymodules/python2.6/matplotlib/__init__.py:835: 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.

  if warn: warnings.warn(_use_error_msg)

Welcome to pylab, a matplotlib-based Python environment [backend: TkAgg].
For more information, type 'help(pylab)'.

In [4]: figure()
Out[4]: <matplotlib.figure.Figure object at 0xaeaa0cc>

In [5]: matplotlib.rcParams['backend']
Out[5]: 'Qt4Agg'

In [6]:


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