[R] Weird behaviour function args in ellipses

[Mario José Marques-Azevedo]

Hi Duncan and David,

Thank you for explanation. I'm really disappointed with this R "resource".
I think that partial match, mainly in function args, must be optional and
not default. We can have many problems and lost hours find errors (it occur
with me). I tried to find a solution to disable partial match, but it seems
that is not possible. Program with hacks for this will be sad.

Best regards!

Mario



On 11 December 2015 at 15:55, David Winsemius <dwinsemius at comcast.net>
wrote:

>
> > On Dec 11, 2015, at 9:40 AM, Mario José Marques-Azevedo <
> mariojmaaz at gmail.com> wrote:
> >
> > Dears,
> >
> > I'm having a weird behaviours when setting arguments in functions.
> >
> > fn <- function(x, st="mean", b=NULL, col.range="black", ...){
> >  dots <- list(...)
> >  cat("col.range =", col.range, "\n")
> >  cat("dots =\n")
> >  print(dots)
> > }
> >
> > fn(1, b=2,col="red")
> >
> > # Output
> > col.range = red
>
> Argument matching is done with `pmatch`. So "col" is a partial match to
> "col.range".
>
> See ?match.arg
>
>
> > dots =
> > list()
> >
> > Why 'col' arguments are not in ellipses, but setting col.range to 'red'?
> >
> > If I change the position of ellipses
> >
> > fn2 <- function(x, ..., st="mean", b=NULL, col.range="black"){
> >  dots <- list(...)
> >  cat("col.range =", col.range, "\n")
> >  cat("dots =\n")
> >  print(dots)
> > }
> >
> > fn2(1, b=2, col="red")
> >
> > # Output
> > col.range = black
> > dots =
> > $col
> > [1] "red"
> >
> > It works! I'm using R version 3.2.2.
>
> It's been that way 'forever'.
>
> >
> > Best regards!
> >
> > Mario
> >
> >       [[alternative HTML version deleted]]
> >
> > ______________________________________________
> > R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> > 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.
>
> David Winsemius
> Alameda, CA, USA
>
>

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