[Python-Dev] PEP 506 secrets module

[Guido van Rossum]

Single-argument randrange(n) is the same as randbelow(n), right? I don't
see any reason to have randbelow() if that's true.

On Fri, Oct 16, 2015 at 11:29 AM, Serhiy Storchaka <storchaka at gmail.com>
wrote:

> On 16.10.15 19:26, Steven D'Aprano wrote:
>
>> On Fri, Oct 16, 2015 at 06:35:14PM +0300, Serhiy Storchaka wrote:
>>
>>> I suggest to add only randrange(). randint() is historical artefact, we
>>> shouldn't repeat this mistake in new module. The secrets module is not
>>> good way to generate dice rolls. In most other cases you need to
>>> generate integers in half-open interval [0; N).
>>>
>>> And randbelow() is absolute redundant. Random._randbelow() is
>>> implementation detail and I inclined to get rid of it (implementing
>>> randrange() in C instead).
>>>
>>
>> This was discussed on Python-Ideas, and there was little consensus there
>> either. (Looks like Tim Peters' prediction is coming true :-)
>>
>> Putting aside your inflammatory description of randint() as a "mistake",
>> if you are correct that in most cases people will need to generate
>> integers in the half-open interval [0...n) then we should keep
>> randbelow, since that is precisely what it does.
>>
>
> Andrew explained the history of the issue (
> http://permalink.gmane.org/gmane.comp.python.ideas/36437). randrange was
> added in 61464037da53 to address a problem with unpythonic randint.
>
> Personally, I have no sense of which of the three functions will be most
>> useful, but if you are right about the half-open [0...n) interval, then
>> randbelow seems to be the right API to offer. But I have seen people
>> argue in favour of randint, and others argue in favour of randrange.
>> Given that these are just thin wrappers or aliases to methods of
>> random.SystemRandom, I don't think there is any harm in providing all
>> three.
>>
>
> Yes, randbelow provides simpler API, but randrange is more familiar for
> Python users due to similarity to range and because it is the public API in
> the random module (unlike to randbelow).
>
>
>
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-- 
--Guido van Rossum (python.org/~guido)
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