how to do random / SystemRandom switch

Matthias Kievernagel mkiever at Pirx.sirius.org
Sat Apr 30 15:28:36 CEST 2011


Peter Otten <__peter__ at web.de> wrote:
> Matthias Kievernagel wrote:
> 
>> In my top-level script I want to select if my program
>> is to use random.xxx functions or the random.SystemRandom.xxx
>> ones. All the other modules shouldn't know about that
>> switch and simply use
>> import random
>> ...
>> return random.randint(1, 6)
>> ...
>> for example.
> 
> You can inject the SystemRandom instance into the sys.modules cache:
> 
>>>> import random
>>>> random
> <module 'random' from '/usr/lib/python2.6/random.pyc'>
>>>> sr = random.SystemRandom()
>>>> import sys
>>>> sys.modules["random"] = sr
> 
> Then use it in the other modules:
> 
>>>> import random
>>>> random
> <random.SystemRandom object at 0x1acdb60>
> 
> Another approach is to monkey-patch the random module:
> 
> import random
> sr = random.SystemRandom()
> random.randrange = sr.randrange
> random.randint = sr.randint
> ...
> 
Thanks a lot. That's what I was looking for.
I'll give both a try.

Regards,
Matthias Kievernagel



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