locator(n=1) or (n=500) as S-plus ?
Prof Brian Ripley
Prof Brian Ripley <firstname.lastname@example.org>
Tue, 26 Jan 1999 11:47:24 +0000 (GMT)
I would much rather you fixed the lack of a type= argument first:
without that the use of n > 1 is not very much use as there can be no
feedback to the user.
S-PLUS devices give some feedback by changing the cursor: R devices I
have seen do not.
> Date: Tue, 26 Jan 1999 10:53:48 +0100
> From: Martin Maechler <email@example.com>
> To: Rfirstname.lastname@example.org
> Subject: Re: locator(n=1) or (n=500) as S-plus ?
> >>>>> "MM" == Martin Maechler <email@example.com> writes:
> MM> There's a non-compatibility between R and S-plus with the default
> MM> argument of the locator() function.
> MM> R has locator(n=1)
> MM> S-plus has locator(n=500, type="n", noclick=F)
> MM> S's default is ``better'' I think, insofar as it means in 99% of
> MM> the cases ``user clicks <left> as many times as wanted and then
> MM> clicks <right> to end''
> MM> Ross Ihaka and his grad students are working on improving this
> MM> interface, I believe, however, I'd propose to just change
> MM> the default of n=1 to n=500 (or another "large" integer in order to
> MM> not copy S exactly).
Why not 99999 or whatever?
> I got 0 feedback..
> What about the following new locator()
> which additionally adds a `msg' argument
> The old behavior is got by
> locator( *, msg="") or
> locator(*, msg=NULL)
> locator <- function(n = 512,
> msg = "Click left to locate points; right to end")
> do.msg <- is.character(msg) && nchar(msg) > 0
> if(do.msg) cat(msg,": ",sep="")
> z <- .Internal(locator(n))# n <= 0 gives error
> if(do.msg) cat("\n")
> x <- z[]
> y <- z[]
> if((n <- z[]) > 0) list(x=x[1:n], y=y[1:n])
> Would anyone not like the default of `msg' writing to the console?
Could you make sure it puts out a "\n" as well? Unfinished lines
in the middle of output are a visual pain, and on line-buffered devices
may not appear at all.
> I've often been startled by functions using locator() and not prompting
> the user to do start clicking in the graphic window at all..
R misses one of S-PLUS's visual clues, of course.
Brian D. Ripley, firstname.lastname@example.org
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: email@example.com