From: Jan T. Kim <jtk_at_cmp.uea.ac.uk>

Date: Fri 08 Apr 2005 - 04:51:26 EST

Date: Fri 08 Apr 2005 - 04:51:26 EST

On Thu, Apr 07, 2005 at 11:58:48AM -0500, Earl F. Glynn wrote:

> "Duncan Murdoch" <murdoch@stats.uwo.ca> wrote in message

*> news:42555459.6040106@stats.uwo.ca...
**> > > Seems to me the conversion from hex to decimal should be system
**> independent
**> > > (and makes working with colors much more convenient). Why isn't this
**> system
**> > > independent now?
**> >
**> > Presumably because nobody thought it was important enough to make it so.
**> > R isn't a low level system programming language, so why should it
**> > treat hex specially?
**>
**> 1) While generally I'd agree with your statement, manipulating colors is one
**> place the ability to convert to/from hex would be quite nice.
**>
**> > rgb(1,0,0.5)
**> [1] "#FF0080"
**>
**> rgb returns a hex string and then R makes manipulating this string somewhat
**> difficult.
*

I'd like to second this opinion. It just occasionally happens that data are available in some variant of hex format, and I've had the impression that getting such data into R is a bit less convenient than it could be.

> One might want to use such color values to convert to a

*> different color space, perform some sort of manipulation in that other color
**> space, and then convert back to rgb.
**>
**> 2) I would think that one of R's mathematical abilities would be to provide
**> a way to convert from any base to base 10, and from base 10 to any base. I
**> haven't found this general math tool yet in R. Working with base-16 (or
**> even base 2 sometimes) could be done with such a general math tool.
*

In fact, the ANSI C function strtol already provides conversion to any base between 2 and 36, so R's mathematical capabilities don't even need to be invoked here.

An R function strtol(x, base), x being a character variable and base an integer between 2 and 36, would probably add a bit of convenience. I've never programmed that, though -- seems that I'm one of those to whom this hasn't been important enough.

If it is done some day, I'd favour the strtol function over having as.numeric interpret the (rather C-ish) 0x prefix. I wasn't aware that this currently works on some platforms (and I'm glad it doesn't interpret the 0 prefix for octal, as C does, making 007 legal and 008 not. ;-) )

Best regards, Jan

-- +- Jan T. Kim -------------------------------------------------------+ | *NEW* email: jtk@cmp.uea.ac.uk | | *NEW* WWW: http://www.cmp.uea.ac.uk/people/jtk | *-----=< hierarchical systems are for files, not for humans >=-----* ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.htmlReceived on Fri Apr 08 04:02:29 2005

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