[Numpy-discussion] packaging scipy (was Re: Simple financial functions for NumPy)

Christopher Barker Chris.Barker@noaa....
Wed Apr 9 13:27:04 CDT 2008

Sorry to be late on this thread, but I was out of town, and I do feel 
strongly about this issue.

Gael Varoquaux wrote:
> For the beginner, "from numpy.all import *" is more confusing than "from
> numpy import *" (which is already confusing).

except that the beginner, nor anyone else, should ever use "import *" 

> I know namespace are good things, but the beginner struggles with them.
> This is why I used the "import *" in my above examples.

You're better off with a good foundation -- really. And particularly for 
a beginner, knowing what comes from numpy, and what from python (or 
other packages) is a "good thing".

It's a mixed bag, but I like namespaces a lot -- there's a lot to be 
said for thinking: I need some stats, an doing something like:

from numpy.stats import stats

That being said, having a numpy.all namespace has its uses, particularly 
for interactive use, but let's not make it the default.

Look at history here:

Everyone used to do "from Numeric import *", now many (most?) folks use 
the numpy namespace, with something like "import numpy as N".

Matplotlib started out with a Matlab like: "from pylab import *", now 
there is a separate namespace for plotting, etc, and a movement towards 
using separate namespaces.

"Namespaces are one honking great idea -- let's do more of those!"

That's "more", not "fewer"

Gael Varoquaux wrote:
> Convention are important, especially in coding.

This is really, really important. What if we all used a different name 
for "self?" -- just as correct, but it would be a lot harder to 
understand other's code.

I really don't get the reluctance -- EVERY major package I've worked 
with has moved AWAY from "import *" (numpy, wxPython, matplotlib, ...). 
We should never, never, recommend it to beginners. Period. And it would 
be very nice to use a standard. I use "import numpy as N", but would be 
quite happy to use "np" or "nx", or anything else short that becomes a 

>  IMHO the
> pylab option is quite nice: matplotlib is nice and modular, but pylab has
> it all. Use whichever you want.

I disagree -- with pylab and numpy, there is constant confusion from 
folks as they move past the beginner stage -- "where did that function 
come from?", "What do I have to change now that I'm embedding my MPL 
code in a GUI?"

"There should be one-- and preferably only one --obvious way to do it."

Maybe there is a large population of folks that never do move past the 
beginner stage -- but I say -- let then use Octave! I use Python 
specifically because it's a more sophisticated language than Matlab.

> The only thing  
> namespaces solve is name collisions imho.

The other one is readability -- I like knowing where things come from, 
and what that have to do with. This is really an augment against "import 
*", but it applied to hierarchical namespaces too -- you can see the 
structure in the code, -- I like that.

> I don't believe that the  
> current numpy has too many names in its basic namespace,

It's a little too big, rather than a lot too small though -- remember 
this thread started from "where do we put financial functions".

> and it  
> already has split out some things into subpackages (fft, random,  
> linear algebra) that have such a potential.

exactly -- so numpy.finance fits right in...

> 3) Some don't like the bloat (in disk space or download sizes) of  
> adding things to numpy. In my case, as long as the addition doesn't  
> make installations any more difficult I don't care.

+1 Easy of installation is far more important than download size.

Brian Granger wrote:
> Simply putting things into
> numpy because of convenience (numpy is easier to install) only
> encourages people to never install or use scipy. 

Actually it's worse -- it discourages us from making scipy easier to 
install. I still don't use it.

But we can save most of this for 1.1 (or 2.0, or...)


Christopher Barker, Ph.D.

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