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Re: how to do random / SystemRandom switch

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  Re: how to do random / SystemRandom switch Peter Otten <__peter__@web.de> - 2011-04-30 15:06 +0200
    Re: how to do random / SystemRandom switch Matthias Kievernagel <mkiever@Pirx.sirius.org> - 2011-04-30 13:28 +0000

#4198 — Re: how to do random / SystemRandom switch

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
...

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#4199

Peter Otten <__peter__@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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