Tricky import question.

[David Poundall]

importedfiles = {}
for f in FileList
f2 = f.split('.')[0] # strip the .py, .pyc
__import__(f2)
s2 = f2+'.main()' # main is the top file in each import
c = compile(s2, '', 'eval')
importedfiles[f2] = eval(c)

'importedfiles' should hold an object reference to the main() function
within each imported file.

The problem is, the import function works but I can't get the object
reference into the imortedfiles dictionary object. the code keeps
telling me

NameError: name 'C1_Dosing' is not defined.

in this instance C1_Dosing is the first file name in the filelist. The
import worked, why not the compile ??

TIA.

[Fredrik Lundh]

Re: Tricky import question.

David Poundall wrote:
[color=blue]
> importedfiles = {}
> for f in FileList
> f2 = f.split('.')[0] # strip the .py, .pyc
> __import__(f2)
> s2 = f2+'.main()' # main is the top file in each import
> c = compile(s2, '', 'eval')
> importedfiles[f2] = eval(c)
>
> 'importedfiles' should hold an object reference to the main() function
> within each imported file.
>
> The problem is, the import function works but I can't get the object
> reference into the imortedfiles dictionary object. the code keeps
> telling me
>
> NameError: name 'C1_Dosing' is not defined.
>
> in this instance C1_Dosing is the first file name in the filelist. The
> import worked, why not the compile ??[/color]

because your __import__ statement didn't assign the returned module
to anything, so there's no C1_Dosing in the current namespace.

assuming that the main function in each module returns something that
you want to store in the importedfiles dictionary, here's a better way to
do it:

m = __import__(f2)
importedfiles[f2] = getattr(m, "main")()

tweak as necessary.

</F>

[David Poundall]

Re: Tricky import question.

Sadly I get this reply when I try that.

AttributeError: 'module' object has no attribute 'main'

I am getting the impression that the value returned from the
__import__() function is only a string reference NOT an object.

I am going to have a go at trying this with the imp' module as that
specifically mentions that an object is returned.

[David Poundall]

Re: Tricky import question.

This worked ...

def my_import(name) :
mod = __import__(name )
components = name.split('.')
for comp in components[1:]:
mod = getattr(mod, comp)
return mod

for reasons given here...

http://www.python.org/doc/2.3.5/lib/built-in-funcs.html

[Bengt Richter]

Re: Tricky import question.

On 25 Oct 2005 06:39:15 -0700, "David Poundall" <david@jotax.co m> wrote:
[color=blue]
>importedfile s = {}
>for f in FileList
> f2 = f.split('.')[0] # strip the .py, .pyc[/color]
importedfiles[f2] = __import__(f2). main
# it sounds like all you want is the above (untested ;-), or
# use __import__(f2). main() if you actually want the _result_ returned by main

Either way, you don't need the following[color=blue]
> __import__(f2)
> s2 = f2+'.main()' # main is the top file in each import
> c = compile(s2, '', 'eval')
> importedfiles[f2] = eval(c)
>
>'importedfiles ' should hold an object reference to the main() function
>within each imported file.[/color]
Do you want a reference to the function, or the result of calling the function?
If you want a reference to the function itself, you should leave off the () after main,
otherwise you will execute the function.
[color=blue]
>
>The problem is, the import function works but I can't get the object
>reference into the imortedfiles dictionary object. the code keeps
>telling me
>
>NameError: name 'C1_Dosing' is not defined.[/color]
probably your first file is C1_Dosing.py (or some other extension after the '.')
so f2 becomes 'C1_Dosing' and s2 becomes 'C1_Dosing.main ()' and you compile that
into code bound to c, and when you try to eval(c), it tries to find C1_Dosing in
the current environment, et voila! you have the error.

When confronted with mysteries such as presented by your code results, I suggest
you intruduce print statements to verify what you are assuming about what it is doing.
E.g., you could print repr(f2) after assignment, and after the __import__ if you thought
it was going to do something to f2 in the local name space, and repr(s2) after the assignment,
etc. to see if I guessed right. Or a quick line to clone for a snapshot of local varibles
at different points might be (untested)
print '\n'.join('%15s : %s'%(k, repr(v)[:60]) for k,v in sorted(locals() .items()))
[color=blue]
>
>in this instance C1_Dosing is the first file name in the filelist. The
>import worked, why not the compile ??[/color]
I think the compile did work. But your code didn't produce a binding for the name
'C1_Dosing' which the code c was looking for when eval(c) was called. If you wanted to
make your code work, perhaps replacing (untested)
__import__(f2)
with
exec '%s = __import__(f2)' %f2 # bind imported module to name specified by f2 string
might have got by the error in eval (c), but I suspect you would want to leave the () off
the .main in any case. And why go through all that rigamarole?
[color=blue]
>
>TIA.
>[/color]
Try it both ways and report back what you found out ;-)

Regards,
Bengt Richter

[Bengt Richter]

Re: Tricky import question.

On 25 Oct 2005 08:51:08 -0700, "David Poundall" <david@jotax.co m> wrote:
[color=blue]
>This worked ...
>
>def my_import(name) :
> mod = __import__(name )
> components = name.split('.')
> for comp in components[1:]:
> mod = getattr(mod, comp)
> return mod
>
>for reasons given here...
>
>http://www.python.org/doc/2.3.5/lib/built-in-funcs.html
>[/color]
Aha. You didn't mention multi-dot names ;-)
But was that the real problem? Your original code
wasn't using anything corresponding to mod above.

Regards,
Bengt Richter

[David Poundall]

Re: Tricky import question.

All I was trying to do with my feeble code attempt, was to return a
reference to the imported module so that I could do...

result = instanceref.mai n()

where main was a function within the import.

Having glanced at the code in the import section of the help files all
morning, when I actually sat down and read it it turned out the example
code was what I needed.

Its always the way.

Many thanks for taking time out to reply Bengt.

[David Poundall]

Re: Tricky import question.

repr() is a new one on me I am afraid, and I have yet to achieve any
decent competance with global and local lists.

As you probaly noticed earlier, I managed to bungle my way through this
time. However, I will log this thread away for when I next get stuck
with a bindings.

Thank you Bengt :-)