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Proper way to pass Queue to process when using multiprocessing.imap()?


> 
> On Sep 3, 2019, at 10:49 AM, Peter Otten <__peter__ at web.de> wrote:
> 
> Israel Brewster wrote:
> 
>> When using pool.imap to apply a function over a list of values, what is
>> the proper way to pass additional arguments to the function, specifically
>> in my case a Queue that the process can use to communicate back to the
>> main thread (for the purpose of reporting progress)? I have seen
>> suggestions of using starmap, but this doesn?t appear to have a ?lazy?
>> variant, which I have found to be very beneficial in my use case. The
>> Queue is the same one for all processes, if that makes a difference.
>> 
>> I could just make the Queue global, but I have always been told not too.
>> Perhaps this is an exception?
> 
> How about wrapping the function into another function that takes only one 
> argument? A concise way is to do that with functools.partial():
> 
> def f(value, queue): ...
> 
> pool.imap(partial(f, queue=...), values)

That looks like exactly what I was looking for. I?ll give it a shot. Thanks!

---
Israel Brewster
Software Engineer
Alaska Volcano Observatory 
Geophysical Institute - UAF 
2156 Koyukuk Drive 
Fairbanks AK 99775-7320
Work: 907-474-5172
cell:  907-328-9145

> 
> 
> 
>> 
>> ---
>> Israel Brewster
>> Software Engineer
>> Alaska Volcano Observatory
>> Geophysical Institute - UAF
>> 2156 Koyukuk Drive
>> Fairbanks AK 99775-7320
>> Work: 907-474-5172
>> cell:  907-328-9145
>> 
> 
> 
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