[R] - round() strange behaviour

David C. Howell David.Howell at uvm.edu
Thu Aug 2 22:42:07 CEST 2007


That is what it is supposed to do.

 From ?round
we get
"Note that for rounding off a 5, the IEC 60559 standard is expected to 
be used, “go to the even digit”. Therefore round(0.5) is 0 and 
round(-1.5) is -2. However, this is dependent on OS services and on 
representation error (since e.g. 0.15 is not represented exactly, the 
rounding rule applies to the represented number and not to the printed 
number, and so round(0.15, 1) could be either 0.1 or 0.2). "



Monica Pisica wrote:
> Hi,
>  
> I am getting some strange results using round - it seems that it depends if the number before the decimal point is odd or even ....
>  
> For example:
>  
>> round(1.5)[1] 2> round(2.5)[1] 2
> While i would expect that round(2.5) be 3 and not 2.
>  
> Do you have any explanation for that?
>  
> I really appreciate your input,
>  
> Monica
>  
>  
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-- 
David C. Howell
PO Box 770059
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