[Tutor] Confused about globals

[Etrade Griffiths]

Hi

I have a series of python programs that plot stuff using PYX.  Common to 
these is the need to read in a list of (well) locations in (X,Y) coords so 
I put that code in a separate module called shared_funcs.py.  The coords 
are stored in dictionaries which I want to use later in the "main" program 
- every time I find a well with data, I can get the well's (x,y) coords by 
looking up the well name in the dictionary.  The code snippet looks like this:

=== main.py ====

# define coord dictionaries for global use

DE={}
DN={}

import shared_funcs()

shared_funcs.get_xy_data()                 # Get coords from file

  ... do plotting stuff


=== shared_funcs.py ===

def get_xy_data():
	in_file=open("well_xy.txt","r")
	for line in in_file
		L=line.split()
		well=L[0]
		x=L[1]
		y=L[2]

		DE[well]=x
		DN[well]=y
	in_file.close()

The problem is that DE and DN appear not to be accessible to get_xy_data - 
presumably this is because shared_funcs.py and main.py don't share the same 
scope.  So, is there any way to let get_xy_data change DE and DN?  I guess 
the obvious way is to pass them to get_xy_data as arguments - but is there 
a more "pythonic" method?  Thanks in advance!