Dale Amon wrote:
On Wed, Apr 29, 2009 at 10:02:46PM -0400, Dave Angel wrote:
The dot syntax works very
predictably, and quite flexibly. The problem was that by using the same
name for module and class, you didn't realize you needed to include both.
It is one of the hazards of working in many very different
languages. But I see where that confusion lies and that is
a useful thing to know.
And in particular if you simply do the following, you can choose between
those modules:
if test:
mod = mymodule1
else:
mod = mymodule2
obj = mod.myclass(arg1, arg2)
Not really applicable to the case I have. There can be lots of
different ones and the input selection comes from a command line
string so...
Please don't sink to exec or eval to solve what is really a
straightforward problem.
I do not really see any other way to do what I want. If
there is a way to get rid of the exec in the sample code
I have used, I would love to know... but I can't see how
to import something where part of the name comes from user
command line input without interpreting the code via exec.
[See the test module I posted.] I'm dealing with something
like this:
myprogram --type WINGTL file.dat
the set of types will have new members added as they are
discovered and I intend to minimize code changes to doing
nothing but create a subpackage directory with the new
modules, drop it in place. New functionality with no
mods to the existing code...
As Scott David Daniels says, you have two built-in choices, depending on
Python version. If you can use __import__(), then realize that
mod = __import__("WINGTL")
will do an import, using a string as the import name. I don' t have the
experience to know how it deals with packages, but I believe I've heard
it does it the same as well.
One more possibility, if you're only trying to get a single package
hierarchy at a time, it might be possible to arrange them in such a way
that the sys.path search order gets you the package you want. Rather
than the top level being a package, it'd be an ordinary directory, and
you'd add it to the sys.path variable so that when you import a
subpackage (which would now really just be a package), you'd get the
right one.
DaveA
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