Kingsford Jones kingsfordjones at gmail.com
Thu Sep 18 00:06:52 CEST 2008

```On Wed, Sep 17, 2008 at 3:11 PM, Gillian Silver <haettulegur at gmail.com> wrote:
> What would I do if I have something like:
>
> x <- rnorm(1:1000)
> y <- rnorm(1:1000)
> z <- x + y
>
> and I want the rainbow to increase with z? (i.e., red for lowest z...all the
> way up to the last color in the rainbow for the highest z)

Do you mean something like the following?

z <- rnorm(1000, sd = sqrt(2))
plot(z, col = rainbow(length(z), end = 5/6)[rank(z)], pch = 19)

>
> On Wed, Sep 17, 2008 at 2:05 PM, stephen sefick <ssefick at gmail.com> wrote:
>
>> plot(1:20, col=rainbow(20))
>>
>> On Wed, Sep 17, 2008 at 4:58 PM, Gillian Silver <haettulegur at gmail.com>
>> wrote:
>> > Hi, how can I create a rainbow gradient in R? For example, let's say I
>> have
>> > a plot of y = x...and I want the plot to go from red -> orange -> yellow
>> ->
>> > green -> blue -> etc.
>> > Right now, I know how to do something like go from red to blue, using the
>> > plotrix library:
>> >
>> > library(plotrix)
>> > redToBlue <-
>> >
>> color.scale(x,redrange=c(0,1),greenrange=c(0,1),bluerange=c(0,1),extremes=c("red","blue"))
>> > plot(x, y, col=redToBlue)
>> >
>> > But I can't figure out how to make the colors a rainbow. (I don't
>> understand
>> > how the redrange, greenrange, and bluerange parameters in color.scale
>> work.)
>> >
>> >
>> > Thanks!
>> >
>> >        [[alternative HTML version deleted]]
>> >
>> > ______________________________________________
>> > R-help at r-project.org mailing list
>> > https://stat.ethz.ch/mailman/listinfo/r-help
>> http://www.R-project.org/posting-guide.html
>> > and provide commented, minimal, self-contained, reproducible code.
>> >
>>
>>
>>
>> --
>> Stephen Sefick
>> Research Scientist
>>
>> Let's not spend our time and resources thinking about things that are
>> so little or so large that all they really do for us is puff us up and
>> make us feel like gods. We are mammals, and have not exhausted the
>> annoying little problems of being mammals.
>>
>>        -K. Mullis
>>
>
>        [[alternative HTML version deleted]]
>
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