Colour points in plot according to third variable

Try this:

library(RColorBrewer)
plot(iris$Sepal.Length,
     col = as.character(cut(iris$Sepal.Length, c(4,6,7,8), labels =
brewer.pal(3, 'Blues'))))



On Thu, Jul 29, 2010 at 2:51 PM, Anna Berthinussen <bs06ab at leeds.ac.uk>wrote:

  

Hi,

I am using the plot function to make a simple plot of my data with one
variable against another and want to colour the data points according to a
third variable. The third variable is continuous (Time) and I want to try
two different ways of colouring the data points, either:

Divide time it into three groups and then colour each data point
accordingly eg. 30-60 minutes in green, 60-90 minutes in red and 90-120
minutes in blue..

or,

Colour the data points using a colour gradient eg. with increasing colour
intensity as time increases..

I think I need to be able to do it within the plot() function as I have
lines fitted from a model which I will also add to the graph.

Any suggestions would be greatly appreciated??

Thanks in advance

Anna

  
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