[Rd] bug in pretty() (PR#1032)

[Prof Brian Ripley]

On Wed, 25 Jul 2001 deepayan@stat.wisc.edu wrote:

>
>
>
> I have the following output from pretty():
>
>
> > pretty(c(-.1, 1)) # note 2nd element
> [1] -2.000000e-01 -2.775558e-17  2.000000e-01  4.000000e-01  6.000000e-01
> [6]  8.000000e-01  1.000000e+00
> > as.character(pretty(c(-.1, 1)))
> [1] "-0.2"                  "-2.77555756156289e-17" "0.2"
> [4] "0.4"                   "0.6"                   "0.8"
> [7] "1"
>
>
> The root cause seems to be here:
>
>
> > 1.2/6 - .2
> [1] -2.775558e-17

You can't expect exact arithmetic.  Using as.character is almost never a
good idea.  I don't think this is a bug, but you should be doing something
more complex if you want to make labels here.

> (It seems that this is not a problem in all installations.)
>
>
> <<insert bug report here>>

!!
>
> --please do not edit the information below--
>
> Version:
>  platform = i686-pc-linux-gnu
>  arch = i686
>  os = linux-gnu
>  system = i686, linux-gnu
>  status =
>  major = 1
>  minor = 3.0
>  year = 2001
>  month = 06
>  day = 22
>  language = R
>
> Search Path:
>  .GlobalEnv, package:ctest, Autoloads, package:base
>
>
>
>
> -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-
> r-devel mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html
> Send "info", "help", or "[un]subscribe"
> (in the "body", not the subject !)  To: r-devel-request@stat.math.ethz.ch
> _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._
>

-- 
Brian D. Ripley,                  ripley@stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272860 (secr)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-
r-devel mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html
Send "info", "help", or "[un]subscribe"
(in the "body", not the subject !)  To: r-devel-request@stat.math.ethz.ch
_._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._