How to pass a global variable to a module?

Dave Angel davea at
Wed Sep 30 00:19:29 CEST 2009

Mars creature wrote:
> <snip>
> I can understand the point that global variables tends to mess up
> programs.
> Assume that I have 10 parameters need to pass to the function. If
> these parameters are fixed, I can use another module to store these 10
> parameters, and import to the module, as suggested by jean-michel. But
> what if these 10 parameters will be changed in the main program?
> Passing the variable to the function as a parameter suggested by Rami
> will certainly do, but I am wondering weather there are other ways.
> What you'd like to code it?
> Thank you very much!
> Jinbo
If we're just talking generalities, we can give you general advice.  
Avoid globals like the plague.  Except for constants, each global should 
require a lot of justification to permit its use. There's no harm in 
passing 10 parameters to a function.  And if some of them are related to 
each other, group them in a tuple, or an object.  If two functions seem 
to have a need to share data without passing it back and forth, they 
probably belong in a class.

Most of the justifiable globals are already there in the standard 
libraries, or at least a good analogy.  For example, stdout is used by 
print, wherever it occurs.  Likewise you may want a global logging 
object.  These are things which act a lot like constants, even though 
they have internal state.


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