[IPython-dev] rant: "%matplotlib inline"

Sat Jul 4 15:57:48 EDT 2015

> On Jul 3, 2015, at 21:53, Fernando Perez <fperez.net at gmail.com> wrote:
> 
> On Fri, Jul 3, 2015 at 9:15 PM, Matthias Bussonnier <bussonniermatthias at gmail.com <mailto:bussonniermatthias at gmail.com>> wrote:
> 
> 
> Well, that would be a step-back from what we have been doing for the last 2 release to remove knowlege of IPython in Jupyter.
> Or, actually break one abstraction that kernel do not know what have started them. 
> If we do one I would prefer the more general one.
> 
> No, it's not IPython-specific, it would simply be recording in any kernel how they were started. That information could be useful in a variety of contexts...

I would technically prefer that the request/response also carry a field of what kind of frontend make a request.
That might allow finer grain behavior of kernel. Anyway, we agree on that, we just don’t use the same terms.

> Well, also define _repr_html_ or _repr_js_ for notebook then.
> The general message is to use our display_protocol the way it is design for matplotlib too. 
> 
> Julia and R don’t need special activation and don’t have these issues, I don’t see why we can’t figure
> out how to do theses things.
> 
> If we can find a cleaner solution with our display protocol, great!  Those ideas are certainly a lot more mature now than when we first hacked up the backend support in the early days of the qt console, and we also have a lot of real-world experience using it, teaching with it, etc.  It's a good time to take stock of that knowledge and update the toolchain...  
> 
> I see one or more PRs coming next week from Scipy :)

Does that mean you are coming ?

> PS: Booooo Pylab :-)
> 
> Actually, I use it a lot, and I think it's a mistake to berate it: %pylab is exactly the right thing to do when you need to quickly have something that puts at your fingertips a bunch of numerical tools.

Well, that was just teasing as the thread started with why not use pylab.

> 
> So yes, I still use, and will continue to use %pylab quite a bit...

I do too, but I think it should only be use by people the **know** what it does. 

We **still** get confused bug report of people telling us that `nbconvert to --python` should include
all the import that IPython does at startup by default[1]. While it does not, people just use %pylab inline
assuming it just set the matplotlib backend for the notebook.

From the issue in [1]

    [...] I just took existing tutorials and
    such which almost always begin with *%pylab inline*. I'll have to
    figure out which of the other imports I'll have to do explicitly in
    the notebook.

    IMHO all of the points you discussed are worth mentioning in some
    highly visible place on the project website and/or documentation, to
    save people the trouble of figuring these things out the hard way.

So you you want to be accurate, if you have a response that tell user %pylab inline just make figures inline. 
you can either correct by :
 - no, %matplotlib inline does it, 
or 
- no, %pylab inline does not only set up the inline backend, but it will also import a bunch of stuff from
  many packages, and be careful it shadows some builtins (in particular sum and any) with the numpy one, 
  and  will make it more work to convert your notebook to .py files. 

Most of the time, the first answer is just the adapted one.

> Remember, readability counts and practicality beats purity...
> Don't forget to import this every now and then, it's always a good antidote against dogmatism.

I do, I agree that %pylab is practical, however IMHO it is against the "Explicit is better than implicit".

I also disagree that it helps with readability, for me it’s neutral for the subpart of %pylab I use.

It also make me think that in the notebook, the text editing is flexible enough, the we could actually expand it to 
what it does. 

import numpy
import matplotlib
from matplotlib import pylab, mlab, pyplot
np = numpy
plt = pyplot
from IPython.core.pylabtools import figsize, getfigs
from pylab import *
from numpy import *

That would make it still “practical”, but explicit; and make it easier to export %pylab’ed notebook to python scripts. 
(and could also be used for %load).

-- 
M

> Cheers,
> 
> f

[1]: https://github.com/jupyter/nbconvert/issues/54 <https://github.com/jupyter/nbconvert/issues/54>
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