Newbie: module structure and import question

Ziong ziongmail-py at
Fri Jan 14 13:02:28 EST 2005

Thx Rob.

yes i know it's related to search path, but i don't know how to set it in a
practical way (beside hard coding).
my concern is, if i want to create a custom module/library, i don't know
what py file will import it and where the working directory should be.
sometime like my example, even i don't know where the root directory of my
module will place, and i expect it can place in anywhere, how should i set
the sys.path?
i know that maybe a stupid  question, please forgive me, i'm just a newbie.
i have read all online documents in but i wouldn't find the

yes,  i'm asking is it normally only put one class in one py file.
thanks for your advice.
But if i put a set of classes in a py file as a module,  will it increase
the dependency of each class?
back to my example, of course, i can put BaseA and ClassA together in one py
file. what should i do when i need to add one more class later, "ClassB",
which also extend BaseA. Put it into the same file or in a new file? if put
in in the same file, i think it should difficult to maintain versioning. i'm
quite confuse in this, maybe because i learn Java before.

Thx again, Rob.

"Rob Emmons" <rmemmons at> ???
news:pan.2005. at ???...
> > hi all,
> > i have question on how to design a module structure.
> > for example, i have 3 files.
> > [somewhere]/
> > [somewhere]/myLib/Base/
> > [somewhere]/myLib/
> > ....
> > .....
> > It's fine when i run
> > however when i run individually, it would fail in import
> > statment since the import path is incorrect.
> > I would like to know is something wrong in my design, or something i
> > missed.
> I think your issue is your module search path.  Take a look at the doc for
> sys.path in the library reference.  These are the directories that python
> searchies for modules.  Usually the "." directory is included in this
> which makes python search the current working directory.  Your example
> fails because your working directories are probably different when you ran
> the two modules.  In any case always consider how you've setup sys.path
> and your libraries and modules.
> > Also, in practical usage, is that one class in one py file?
> I'm not exactly clear what your asking -- but I think yor asking if you'd
> normally only put one class in one py file.  My answer is no -- generally
> you'd put many functions and classes in each py file.  Modules are high
> level and should be used to create libraries essentailly -- this means
> many fucntions and classes per module.
> Rob

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