[R] strange behavior of the compare operator

[jim holtman]

FAQ 7.31

Jim Holtman
Data Munger Guru

What is the problem that you are trying to solve?
Tell me what you want to do, not how you want to do it.


On Fri, Oct 3, 2014 at 8:31 AM, Matthias Salvisberg
<matthias.salvisberg at gmail.com> wrote:
> I had a strange behavior of a function written a few days ago. I
> pointed the problem down to the following minimal example.
>
> can anyone explain why the following comparisons don't reply the
> same"correct" answer?
>
>
> Thanks for your reply!
>
> Matthias
>
>
>
>
> R version 3.1.1 (2014-07-10) -- "Sock it to Me"
> Copyright (C) 2014 The R Foundation for Statistical Computing
> Platform: i386-w64-mingw32/i386 (32-bit)
>
> R is free software and comes with ABSOLUTELY NO WARRANTY.
> You are welcome to redistribute it under certain conditions.
> Type 'license()' or 'licence()' for distribution details.
>
> R is a collaborative project with many contributors.
> Type 'contributors()' for more information and
> 'citation()' on how to cite R or R packages in publications.
>
> Type 'demo()' for some demos, 'help()' for on-line help, or
> 'help.start()' for an HTML browser interface to help.
> Type 'q()' to quit R.
>> sessionInfo()R version 3.1.1 (2014-07-10)
> Platform: i386-w64-mingw32/i386 (32-bit)
>
> locale:
> [1] LC_COLLATE=German_Switzerland.1252
> LC_CTYPE=German_Switzerland.1252
> LC_MONETARY=German_Switzerland.1252 LC_NUMERIC=C
> [5] LC_TIME=German_Switzerland.1252
>
> attached base packages:
> [1] stats     graphics  grDevices utils     datasets  methods   base
>
> loaded via a namespace (and not attached):
> [1] tools_3.1.1> > rm(list = ls())> > myDataFrame <- data.frame(var1 =
> seq(from = -1, to = 0, by = 0.01))> > any(myDataFrame$var1 ==
> (0.68-1))[1] TRUE> > any(myDataFrame$var1 == -0.32)[1] FALSE> >
> myDataFrame$var1[69][1] -0.32> > > str((0.68-1)) num -0.32> str(-0.32)
> num -0.32> str(myDataFrame$var1) num [1:101] -1 -0.99 -0.98 -0.97
> -0.96 -0.95 -0.94 -0.93 -0.92 -0.91 ...
>
>         [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.