[R] numeric comparison error

[MacQueen, Don]

What Jeff, said, plus to see it explicitly:

> print(cpgbins[5:7], digits=18)
[1] 0.200000000000000011 0.250000000000000000 0.300000000000000044

> print(c(0.2, 0.25, 0.3), digits=18)
[1] 0.200000000000000011 0.250000000000000000 0.299999999999999989

-Don

--
Don MacQueen
Lawrence Livermore National Laboratory
7000 East Ave., L-627
Livermore, CA 94550
925-423-1062
Lab cell 925-724-7509
 
 

On 6/18/18, 2:53 PM, "R-help on behalf of Jeff Newmiller" <r-help-bounces using r-project.org on behalf of jdnewmil using dcn.davis.ca.us> wrote:

    FAQ 7.31, or take a university course in numerical analysis.
    
    https://cran.r-project.org/doc/FAQ/R-FAQ.html#Why-doesn_0027t-R-think-these-numbers-are-equal_003f
    
    On June 18, 2018 2:45:29 PM PDT, Brian Smith <bsmith030465 using gmail.com> wrote:
    >Hi,
    >
    >I am a little bit perplexed at why I am getting some values as FALSE:
    >
    >> cpgbins <- seq(0,1,0.05)
    >
    >> cpgbins
    >[1] 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 0.55 0.60
    >0.65
    >0.70 0.75 0.80 0.85 0.90 0.95 1.00
    >
    >> cpgbins[1] == 0.00
    >[1] TRUE
    >> cpgbins[2] == 0.05
    >[1] TRUE
    >> cpgbins[3] == 0.10
    >[1] TRUE
    >> cpgbins[4] == 0.15
    >[1] FALSE
    >> cpgbins[5] == 0.20
    >[1] TRUE
    >> cpgbins[6] == 0.25
    >[1] TRUE
    >> cpgbins[7] == 0.30
    >[1] FALSE
    >
    >> class(cpgbins)
    >[1] "numeric"
    >
    >> class(cpgbins[7])
    >[1] "numeric"
    >
    >What is the cause for this?
    >
    >thanks!!
    >
    >	[[alternative HTML version deleted]]
    >
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    -- 
    Sent from my phone. Please excuse my brevity.
    
    ______________________________________________
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