[R-SIG-Mac] Unexpected output from round()

[John Maindonald]

I cannot reproduce it (R version 3.2.0 Patched (2015-04-19 r68206)) in a terminal window:

> dput(pi)
3.14159265358979
> round(dput(pi),2)
3.14159265358979
[1] 3.14
> Cl <- c(82.9888290534313, 100.544763749464)
> dput(Cl)
c(82.9888290534313, 100.544763749464)
> round(dput(Cl),2)
c(82.9888290534313, 100.544763749464)
[1]  82.99 100.54
> sessionInfo()
R version 3.2.0 Patched (2015-04-19 r68206)
Platform: x86_64-apple-darwin13.4.0 (64-bit)
Running under: OS X 10.10.3 (Yosemite)

locale:
[1] en_NZ.UTF-8/en_NZ.UTF-8/en_NZ.UTF-8/C/en_NZ.UTF-8/en_NZ.UTF-8

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base  

John Maindonald             email: john.maindonald at anu.edu.au

> On 13/06/2015, at 12:39, Dennis Fisher <fisher at plessthan.com> wrote:
> 
> R 3.2.0
> OS X
> 
> Colleagues
> 
> I received unexpected output from a command issued in a terminal window:
> 
>> dput(CI)
> c(82.9888290534313, 100.544763749464)
> 
>> round(dput(CI), 2)
> c(82.9888290534313, 100.544763749464)
> [1]  82.98999999999999 100.54000000000001
> 
> I expected the result of the second command to be:
> 	82.99   100.54
> 
> Interesting, the problem also occurs if I round to 5 or 8 digits.  
> 
> Of note, the problem does NOT occur in R GUI or in Windows.
> 
> I am aware of FAQ 7.31 (Why doesn’t R think these numbers are equal?) but I don’t see how this could be manifestation of that issue.
> 
> I am curious as to the explanation of this issue.
> 
> Dennis
> 
> 
> Dennis Fisher MD
> P < (The "P Less Than" Company)
> Phone: 1-866-PLessThan (1-866-753-7784)
> Fax: 1-866-PLessThan (1-866-753-7784)
> www.PLessThan.com
> 
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