[R] operators %/% bug?

[Spencer Graves]

Consider also the following: 

a <- 1.2
b <- 1.0

 > (a-b)%%.1
[1] 0.1
 > (a-b)%/%.1
[1] 1
 > .2%%.1
[1] 0
 > .2%/%.1
[1] 2

      This performs as described on "?%/%".  In particular, the second 
paragraph under "Value": 

 '%%' indicates 'x mod y' and '%/%' indicates integer division.  It
     is guaranteed that 'x == (x %% y) + y * ( x %/% y )' (up to
     rounding error) unless 'y == 0' where the result is 'NA_integer_'
     or 'NaN' (depending on the 'typeof' of the arguments).  See <URL:
     http://en.wikipedia.org/wiki/Modulo_operation> for the rationale.

      hope this helps. 
      Spencer

jim holtman wrote:
> FAQ 7.31
>
> a-b != 0.2
>
>   
>> a <- 1.2
>>
>> b <- 1.0
>>
>> a-b-.2
>>     
> [1] -5.551115e-17
>   
>
>
>
> On 3/31/08, Lo, Ken <Ken.Lo at roswellpark.org> wrote:
>   
>> Dear  all,
>>
>>
>>
>> I have come across a strange behavior of the %/% operator, and I wasn't
>> sure if this was intended.
>>
>>
>>
>> i.e.
>>
>> a <- 1.2
>>
>> b <- 1.0
>>
>> (a-b) %/% 0.1  results in 1?
>>
>> Whereas
>>
>> 0.2 %/% 0.1 results in 2.
>>
>>
>>
>> Am I missing something obvious here?  It seems to be consistent up to R
>> 2.6.0 running in WinXP (haven't upgraded yet).
>>
>>
>>
>> Best,
>>
>>
>>
>> Ken
>>
>>
>>
>> This email message may contain legally privileged and/or confidential information.  If you are not the intended recipient(s), or the employee or agent responsible for the delivery of this message to the intended recipient(s), you are hereby notified that any disclosure, copying, distribution, or use of this email message is prohibited.  If you have received this message in error, please notify the sender immediately by e-mail and delete this email message from your computer. Thank you.
>>        [[alternative HTML version deleted]]
>>
>> ______________________________________________
>> R-help at r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>>
>>     
>
>
>