[R] bug when subtracting decimals?

[Dimitris Rizopoulos]

this is a (very) Frequently Asked Question; check:

http://cran.r-project.org/doc/FAQ/R-FAQ.html#Why-doesn_0027t-R-think-these-numbers-are-equal_003f


Best,
Dimitris


wolfgang.siewert wrote:
> Try this:
> 
> 0.7-0.3==0.4
> (We get FALSE)
> 0.7-0.3<0.4
> (We get TRUE)
> 
> but
> 0.8-0.3==0.5
> (TRUE)
> 0.8-0.3<0.5
> (FALSE)
> 
> Funny, he?
> 
> There is a way around: 
> round(0.7-0.3,1)==0.4
> (TRUE)
> 
> Obviously there is a problem with some combinations of decimal subtractions,
> that - we have the feeling - shouldt be solved.
> 
> Best regards
> Sven & Wolfgang

-- 
Dimitris Rizopoulos
Assistant Professor
Department of Biostatistics
Erasmus University Medical Center

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