[R] round() - strange results

[Chuck Cleland]

?round

'round' rounds the values in its first argument to the specified
number of decimal places (default 0). Note that for rounding off a
5, the IEEE standard is used, "_go to the even digit_". Therefore
'round(0.5)' is '0' and 'round(-1.5)' is '-2'.

Dongseok Choi wrote:
> Hello,
>  
>   I found that round() does not behave as I expected.
>   Have you had similar experience as following?
>  
> 
>>x<-seq(0.5,10.5,by=1)
>>x
> 
>  [1]  0.5  1.5  2.5  3.5  4.5  5.5  6.5  7.5  8.5  9.5 10.5
> 
>>round(x)
> 
>  [1]  0  2  2  4  4  6  6  8  8 10 10
> 
>>cbind(x,round(x))
> 
>          x   
>  [1,]  0.5  0
>  [2,]  1.5  2
>  [3,]  2.5  2
>  [4,]  3.5  4
>  [5,]  4.5  4
>  [6,]  5.5  6
>  [7,]  6.5  6
>  [8,]  7.5  8
>  [9,]  8.5  8
> [10,]  9.5 10
> [11,] 10.5 10
> 
>  
>   Is this a well-known bug?
>  
> Thanks in advance,
>  
>  
> Dongseok Choi, Ph.D.
> Assistant Professor
> Division of Biostatistics
> Department of Public Health & Preventive Medicine
> Oregon Health & Science University
> 3181 SW Sam Jackson Park Road, CB-669
> Portland, OR 97239-3098
> TEL) 503-494-5336
> FAX) 503-494-4981
> choid at ohsu.edu
> 
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> 
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-- 
Chuck Cleland, Ph.D.
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