How to write good Python objects?
revanna at mn.rr.com
Mon Oct 27 16:57:14 CET 2003
Not sure if ya'll have seen these references to distutils and windows. I'm
forwarding to make sure we keep it in mind when we're working on our book.
On Fri, 24 Oct 2003 07:01:52 +0100, Marijan Tadin wrote:
>> One other thing -- I would like to be able to include a statement in my
>> program to the effect of: "from my_package import my_function_or_class".
>> Python seems to look for .pyc files in the /Lib folder. By placing a
>> .py file in /Lib, I got it to compile, and to be recognized by an import
>> statement. Is this the right way for users to package their own code?
>> It seems kludgy to me.
> AFAIK if you want to import a python module (actually *.py file), you can
> place it in /Lib subdirectory of python distribution, but I think this
> subdirectory schould better stay reserved for modules from standard python
> You can put your module in any directory, and then add this subdirectory
> to the PYTHONPATH environment variable of your operating system. I've been
> doing this for a while, but then I ended with unmanageable cluster of
> files distributed somewhere on my computer. I think the best way is to use
> distutilities (Distributing Python Modules link in your python
> documentation). I've studied it a few days ago, and it is much easier to
> use (at least for simple things) than I had thought before.
> There is also a /lib/site-packages directory in your python distribution,
> if you put your *.py file in it, you can allways import it in your
> application, and it is also intended as directory for third-party python
> modules, and distutilities will install your modules into this
> subdirectory. I 'd recommend you to use packages (section 6.4 Packages in
> the tutorial in your python documentation) if you are not allready doing
> so, because otherwise you'll probably soon get name clashes.
> If you use distutillities, you get two extras too: 1. You can easily make
> a Windows installer for your library, and if you install your library this
> way, it will be registerd by OS, so if you want to uninstall your library,
> you can do it as for any other windows programm.
> 2. If you want to compile C extension, the easiest way to do so is with
> distutilities. The first time I succeeded to do so, was with help from
> some web post by Alex Martelli (maybe it is in Python recepies, but I'm
> not sure). Most information how to do this is rather linux oriented.
> Actually it is not difficult to do so on Windows (also with Mingw
> compiler) but there is, AFAIK, no detailed (from begin to end at one
> place) instruction how to do it for dummies (I still feel like one, so the
> worst thing that can happen is a hint: "look into your compiler
> documentation"), it is rather distributed over the web.
>> I have written one nice, self-contained object that contained a DNA
>> sequence, and various functions to manipulate the data therein. My
>> wxPython GUI objects, in contrast, are in a state of constant flux.
>> Rather than importing and reusing a piece of code, I find myself copying
>> the code into my new program and playing with it, just a bit. I'm
>> starting to believe that writing a good GUI object, one that you can
>> really reuse, is actually quite hard. Yes, I know that you can derive a
>> new object that overrides properties of your old object. Should I find
>> myself doing this for every object that I write?
> I do not feel competent enough to give much advice here, but I believe
> that, if you start to copy and paste your code, you should reconsider your
> design. But, on the other hand, if you intend your library to be used by
> others, to many classes and inheritance can be cumbersome. I remember
> trying to use some Java library, which can do great things, but in order
> to do simplest things with it, I schould use dozen classes, where each of
> them was e.g. 5-th or 10-th in some inheritance hierarchy, and you can
> imagine the fun of finding documentation of the class-methods I wanted to
> use. I can not judge if it is OK for complex library which is intended to
> be used by professional programmers.
>> At the beginning of 2003, I was a frustrated computer user, and lapsed
>> programmer, with problems to solve that screamed for programming. Thanks
>> to the Python language and community, I am a programmer once again.
> I am actualy weather forecaster, and I do some programming in my spare
> time. I can remember learning C++ for about 6-7 months, and then learning
> Java for about 3-4 months, and still not beeing able to open text file and
> do some simple processing (which I could have done easily in Fortran77
> before) without looking in a book . The best advice I've found in the book
> "Thinking in Java", was to have a look at Python.
> Marijan Tadin
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