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From: Wolfgang Maier <wolfgang.maier@biologie.uni-freiburg.de>
Newsgroups: comp.lang.python
Subject: Re: How to simulate C style integer division?
Date: Thu, 21 Jan 2016 15:22:12 +0100
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On 1/21/2016 15:00, Jussi Piitulainen wrote:
> Steven D'Aprano writes:
>
>> So my guess is that the fastest, and certainly the most obvious, way
>> to get the same integer division behaviour as C99 would be:
>>
>> def intdiv(a, b):
>>      # C99 style integer division with truncation towards zero.
>>      n = a//b
>>      if (a < 0) != (b < 0):
>>          n += 1
>>      return n
>
> You should only increment if there is a (non-zero) remainder.
>

Right. Merging Steven's suggestion and fractions.Fraction.__trunc__ 
implementation I think the right answer may be:

def intdiv2(a,b):
     # C99 style integer division with truncation towards zero.
     if (a < 0) != (b < 0):
         return -(-a // b)
     else:
         return a // b

Cheers,
Wolfgang


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