multiprocessing and dictionaries

[Chris Rebert]

On Sun, Jul 12, 2009 at 10:16 AM, Bjorn Meyer<bjorn.m.meyer at gmail.com> wrote:
> I am trying to convert a piece of code that I am using the thread module with
> to the multiprocessing module.
>
> The way that I have it set up is a chunk of code reads a text file and assigns
> a dictionary key multiple values from the text file. I am using locks to write
> the values to the dictionary.
> The way that the values are written is as follows:
>        mydict.setdefault(key, []).append(value)
>
> The problem that I have run into is that using multiprocessing, the key gets
> set, but the values don't get appended.

Don't have much concurrency experience, but have you tried using a
defaultdict instead?
It's possible its implementation might solve the problem.
http://docs.python.org/dev/library/collections.html#collections.defaultdict

Cheers,
Chris
-- 
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