[Tutor] Understanding (Complex) Modules
Wayne Watson
sierra_mtnview at sbcglobal.net
Thu Mar 4 02:24:35 CET 2010
First a little preamble before my questions.
Most of my work in Python has required modifying a program that uses
modules that were imported by the original program. I've made some use
of modules on a command line like math, and have used the idea of a
qualifier. On occasion, I've used examples from matplotlib that
required from matplotlib.image import AxesImage. Further, I've created
some simple classes, and produced objects with them. No use of
inheritance though. So far so good. In a few places, it is said
modules are objects. I'm slightly puzzled by that, but in some way it
seems reasonable from the standpoint of period notation. So far I have
not created a module.
In Lutz's and Ascher's Learning Python, ed. 2, chap. 16, they describe
the following example, among others:
module2.py as
print "starting to load ..."
import sys
def func(): pass
class klass: pass
print "done loading."
Their description of its use is quite readable. It shows that there is
some more to a module than a list of defs, for example.
Here comes the questions. Recently I began to use matplotlib, scipy, and
pylab, mostly matplotlib. I've ground out a few useful pieces of code,
but I'm fairly baffled by the imports required to get at various
elements, of say, matplotlib (MPL). Some of the MPL examples use of
imports make sense, but how the writer pulled in the necessary elements
is not. How does one go about understanding the capabilities of such
modules? MPL seems to have a lot of lower level components. Some of them
are laid out over numerous pages as in the form of a, say, English
language, description. How does one decipher this stuff. For example,
open the module in an editor and start looking at the organization? I
thinkthe so called MPL guide ins 900 pages long. Even the numpy guide
(reference?), I believe borders on 1000 pages. There must be some way to
untangle these complex modules, I would think. Some of the tutorials
seem nothing more than a template to follow for a particular problem.
So far, looking at the plentiful number of examples of MPL, and probably
some of the other modules mentioned above have not provided a lot of
insight.
Is there some relationship between modules and objects that I'm not
seeing that could be of value?
--
Wayne Watson (Watson Adventures, Prop., Nevada City, CA)
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