On Nov 18, 2011, at 10:43 AM, Joris Meys wrote:
> I have stumbled across some behaviour in R that I really can't place,
> and that makes coding a bit tricky. I know that I can work around it
> when explicitly checking for missing arguments, but still...
> I have two functions. I have a first function based on paste
>
> fun1 <- function(x,y){
> print(missing(y))
> paste(x,'X',sep=y)
> }
>
> If I try this function without specifying `y`, I get the (expected)
> error message:
>
> > fun1(letters[1:6])
> [1] TRUE
> Error in paste(x, "X", sep = y) :
> argument "y" is missing, with no default
>
> The second one with round :
> fun2 <- function(x,y){ print(missing(y)) round(x,digits=y) }
> If I try this function without specifying `y`, it works unexpectedly
> whereas it shouldn't :
> > fun2(100.1) [1] TRUE [1] 100
> In my view, fun1 should definitely give the error message as well, as
> it is not intended to have a default behaviour when y is missing.
> Still, the round() function ignores the fact y is missing. Is this by
> design, is there a check missing in round, or is something else going
> on that I am overlooking?
>
> round
function (x, digits = 0) .Primitive("round")
it has a default so it is fine for digits to be missing since it will have
value 0 in that case ...
Cheers,
S
> Cheers
> Joris
>> sessionInfo()
> R version 2.14.0 (2011-10-31)
> Platform: i386-pc-mingw32/i386 (32-bit)
>
> locale:
> [1] LC_COLLATE=English_United Kingdom.1252
> [2] LC_CTYPE=English_United Kingdom.1252
> [3] LC_MONETARY=English_United Kingdom.1252
> [4] LC_NUMERIC=C
> [5] LC_TIME=English_United Kingdom.1252
>
> attached base packages:
> [1] stats graphics grDevices utils datasets methods
> [7] base
>
> loaded via a namespace (and not attached):
> [1] tools_2.14.0
>
> --
> Joris Meys
> Statistical consultant
>
> Ghent University
> Faculty of Bioscience Engineering
> Department of Mathematical Modelling, Statistics and Bio-Informatics
>
> tel : +32 9 264 59 87
> joris.m...@ugent.be
> -------------------------------
> Disclaimer : http://helpdesk.ugent.be/e-maildisclaimer.php
>
> ______________________________________________
> R-devel@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel
>
>
______________________________________________
R-devel@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-devel
