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Date: Mon, 23 Feb 2015 11:36:05 -0700
From: Michael Torrie <torriem@gmail.com>
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Subject: Re: Best practice: Sharing object between different objects
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On 02/23/2015 11:10 AM, Rob Gaddi wrote:
> So I'd solve it with module level global variables.  It's semi-frowned 
> upon on software stuff because it creates an unintentional shared state 
> between different modules, but you really HAVE a shared state, so it 
> needs to be dealt with.

I would also do it with a module attribute.  In my mind that's exactly
the right way to go.

But I disagree that it's frowned on or a bad thing. A module is a
completely appropriate place to store state.  In fact a module is an
object, but a special one that can only be instantiated once.  So as far
as patterns go, a module is a singleton. Almost any time in Python you
have something that you want to have exactly one instance of in your
program, you don't want to define a class but rather just use a module.

Any code in a module can be considered the constructor. It executes only
once in your program when the module is first imported, no matter how
many times its imported after that.

I often use a module to store configuration that is shared across
modules in my projects.