Using a dictionary to pass data to/from embedded python functions

[wardm]

Thanks again for your help, I agree, it seems I need to read a good book on 
Python.

One last question, will Python allow me to add new items to 
InterfaceModule.VarDictionary
from the Python functions I call ?


"Alex Martelli" <aleax at mac.com> wrote in message 
news:1hjytek.1gh1ur81so4q0tN%aleax at mac.com...
> wardm <wardm66 at gmail.com> wrote:
>
>> Thanks Alex for your help, (and advice on focusing the point of my
>> question).
>>
>> I was able to compile and run your example OK, but when I try to use the
>> "VarDictionary" in the
>> MyScriptModule.py code, I get an exception.
>>
>> I  added the following code to the C app just to add two entries to the
>> Dictionary
>>
>>  PyDict_SetItemString( m_pVarDictionary, "tk1",
>> Py_BuildValue("s","test1Val"));
>>  PyDict_SetItemString( m_pVarDictionary, "tk2",
>> Py_BuildValue("s","test2Val"));
>>
>> Then tried various things in the Python code to display the contents of 
>> the
>> "VarDictionary",
>> such as adding the "print VarDictionary" below.
>>
>> import InterfaceModule
>>
>> def functionName():
>>     print "hello"
>>     print dir(InterfaceModule)
>>     print "that's all"
>>  print VarDictionary
>
> Note the wrong indentation in this latter print statement: this would
> already cause a syntax error (unless the leading 'p' happened to be
> aligned with the leading 'd' of 'def', in which case the function would
> be terminated, the latest print would happen at import-time, and the
> FOLLOWING statement:
>
>>     return
>
> ...would then be a syntax error (return outside of function).  But,
> there's more:
>
>
>> Even though "VarDictionary " is in the Dir, every time I try to use the
>> "VarDictionary" the program fails.
>
> "VarDictionary" is in the dir(...) *** of InterfaceModule ***, of
> course, so you need to refer to it as InterfaceModule.VarDictionary in
> your Python code -- the barename, nor qualified by modulename, just will
> not work, of course!!!
>
> Adding the two C code lines you quote, and changing the Python example
> code to:
>
> def functionName():
>    print "hello"
>    print dir(InterfaceModule)
>    print "VarDictionary is:", InterfaceModule.VarDictionary
>    print "that's all"
>
> changes that part of the output to:
>
> hello
> ['VarDictionary', '__doc__', '__name__']
> VarDictionary is: {'tk2': 'test2Val', 'tk1': 'test1Val'}
> that's all
>
>
> With all due respect, it looks like you're trying to run before you can
> walk -- or more specifically, to embed Python in C++ before you become
> familiar with the most elementary and fundamental aspects of Python,
> such as indentation and the need to qualify compound names.  You might
> want to consider getting a good Python book -- such as, my own Python in
> A Nutshell (2nd ed), Aahz and Stef Maruch's Python For Dummies, Wesley
> Chun's Core Python Programming (2nd ed) -- they're all very recent (mine
> is just out, Aahz's and Stef's I believe is due to hit bookstores in
> September or October), and any of them might serve you well (if you're
> OK with books not necessarily covering the very latest release of Python
> [and the issues you're having suggest that this is not really the
> problem!], there are many other good books, such as Magnus Lie Hetland's
> "Beginning Python", Beazley's "Python Essential Reference", Lutz and
> Ascher's "Learning Python",