How to pass parameter when importing a module?

[Bo Peng]

Dear list,

What I would like to do is something like:

In myModule.py ( a wrapper module for different versions of the module),

if lib == 'standard':
from myModule_std import *
elsif lib == 'optimized'
from myModule_op import *

but I do not know how to pass variable lib to myModule.py to achieve the
following effect:
[color=blue][color=green][color=darkred]
>>> lib = 'standard'
>>> from myModule import * # actually import myModule_std[/color][/color][/color]

From what I have read, from .... does not take any parameter. Maybe I
should use environmental variables?
[color=blue][color=green][color=darkred]
>>> os.putenv('lib' , 'standard')
>>> from myModule import *[/color][/color][/color]

myModule.py
-------------
import os
lib = os.getenv('lib' )
...


or use a separate module?

param.py
---------

para = {}
def setParam(key, val):
para[key] = val

main session
------------[color=blue][color=green][color=darkred]
>>> import param
>>> param.setParam( 'lib','standard ')
>>> from myModule import *[/color][/color][/color]

in myModule.py
--------------
from param import para
try:
lib = para['lib']
except:
lib = 'standard'
...

Is there an established approach for this problem?

Many thanks in davance.
Bo

=============== =============== =============== =============== =============== ====
FULL STORY:

I have several modules all (SWIG) wrapped from the same C++ source code
but with different compiling flags. For example,

myModule_std (standard module)
myModule_op (optimized, without error checking)
...

These modules are put directly under /.../site-packages . To load a
module, I use, for example

from myModule_op import *

This works fine until I need to write some helper functions for
myModule_?? in another module myHelper.py since I do not know which
myModule is being used

from myModule?? import A,B

I find one solution

# find out which module is being used
import sys
if 'myModule_op' in sys.modules.key s():
from myModule_op import A,B
else:
from myModule_std import A,B

but not completely satisfied. Therefore, I am writing a 'wrapper' module
myModule that can load one of the myModule_?? modules according to user
supplied info.

[Swaroop C H]

Re: How to pass parameter when importing a module?

On Sun, 20 Mar 2005 10:18:14 -0600, Bo Peng <bpeng@rice.edu > wrote:[color=blue]
> What I would like to do is something like:
> In myModule.py ( a wrapper module for different versions of the module),
> if lib == 'standard':
> from myModule_std import *
> elsif lib == 'optimized'
> from myModule_op import *[/color]

Suggestion: Maybe you use builtin `__import__` to load a module ? Note
that in this way, you'll have to use the module name prefix.


--
Swaroop C H
Blog: http://www.swaroopch.info
Book: http://www.byteofpython.info

[André Roberge]

Re: How to pass parameter when importing a module?

Bo Peng wrote:[color=blue]
> Dear list,
>
> What I would like to do is something like:
>
> In myModule.py ( a wrapper module for different versions of the module),
>
> if lib == 'standard':
> from myModule_std import *
> elsif lib == 'optimized'
> from myModule_op import *
>
> but I do not know how to pass variable lib to myModule.py to achieve the
> following effect:
>[/color]
How about this:
#===== constants.py
lib = whatever #assigned somewhere else

#===== myModule.py
from constants import lib

etc.

André

[Serge Orlov]

Re: How to pass parameter when importing a module?

Bo Peng wrote:[color=blue]
> Dear list,
>
> What I would like to do is something like:
>
> In myModule.py ( a wrapper module for different versions of the
> module),
> if lib == 'standard':
> from myModule_std import *
> elsif lib == 'optimized'
> from myModule_op import *
>
> but I do not know how to pass variable lib to myModule.py to achieve
> the following effect:
>[color=green][color=darkred]
> >>> lib = 'standard'
> >>> from myModule import * # actually import myModule_std[/color][/color][/color]

[snip]

Take a look at wxPython versioning:

http://wiki.wxpython.org/index.cgi/MultiVersionInstalls

The most simple usage looks like

import wxversion
wxversion.selec t("2.4")
import wx
Serge.

[Bo Peng]

Re: How to pass parameter when importing a module?

[color=blue]
>
> Take a look at wxPython versioning:
> http://wiki.wxpython.org/index.cgi/MultiVersionInstalls
>
> The most simple usage looks like
>
> import wxversion
> wxversion.selec t("2.4")
> import wx
> Serge.
>[/color]

This is essentially my second method: using another module to set
parameter for myModule. Since wxPython uses this method, I suppose this
is the standard approach for this problem.

Thanks.
Bo