Diez B. Roggisch
3/3/2010 9:18:00 AM
Am 02.03.10 21:41, schrieb mk:
> Jerry Hill wrote:
>> Just import subprocess at the top of your module. If subprocess
>> hasn't been imported yet, it will be imported when your module is
>> loaded. If it's already been imported, your module will use the
>> cached version that's already been imported.
>>
>> In other words, it sounds like Python already does what you want. You
>> don't need to do anything special.
>
> Oh, thanks!
>
> Hmm it's different than dealing with packages I guess -- IIRC, in
> packages only code in package's __init__.py was executed?
I don't understand this. But there is no difference regarding caching &
execution between packages and modules.
Importing a package will execute the __init__.py, yes. But only once. As
will importing modules execute them, but only once.
All subsequent imports will just return the created module-object.
Unless you import something under a new name! That is, you can alter the
sys.path and then import a package/module under a different name -
python won't detect that.
Simplest example ist this:
---- test.py ----
class Foo(object):
pass
if __name__ == "__main__":
import test # import ourselves
# this holds, because we have
# __main__.Foo and test.Foo
assert Foo is not test.Foo
---- test.py ----
However, unless you mess with python, this is none of your concern.
Diez