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]

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 ??

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]

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]

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]

importedfiles = {}
for f in FileList
f2 = f.split('.')[0] # strip the .py, .pyc

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

__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.

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.

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.

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()))

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

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?

TIA.

Try it both ways and report back what you found out ;-)

Regards,
Bengt Richter

 

[Bengt Richter]

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

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]

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.main()

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]

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