[R] color code from csv

Jim Lemon jim at bitwrit.com.au
Sun Oct 5 12:04:44 CEST 2008

kerfuffle wrote:
> hi folks,
> this is driving me up the wall.  Apologies for posting twice in the same
> week, I'm writing up a thesis.  I wish to color-code some dots in an xy
> plot.  I've got a csv file with various elements, one of which is the
> color-key (with the header 'color').  If the color-key is decimal (eg.
> 1,2,3) then I can use
> plot (X ~ Y, col=data$color) 
> The problem, however, is that using decimal numbers I can only produce 8
> colors.  It starts to recyle them after that (so, if possible values of my
> color column are 1,2,3,4,5,6,7,8,9,10,11, the values 1 and 9 both produce
> red, 2 and 10 produce black).  However, I knew I could get more colors by
> using hexadecimal (tested with the legend)  So, I carefully produced a csv
> file with hexadecimal values instead of decimal ones (eg. elements in the
> column are #ffffff, #ff0000) but if I use col=data$color it doesn't work,
> the entire plot is white.  If I use these set of hexadecimal values in the
> legend, it works fine and I get lovely colors.  
Hi kerfuffle,
You might want to look at color.scale in the plotrix package that 
transforms numeric values into colors as well as the rainbow function 
that Sarah mentioned.


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