[R] colour scheme in: plot(survfit.model)

[Federico Calboli]

Dear All,

I would like to ask a question on the colour scheme I can specify for a 

plot(survfit.model).

I have four lines of Drosophila, kept at 3 different temperatures. About
100 individuals per line and temperature were scored, no censoring.

the data looks like:

line	temp	day	status
line1	18	23	1
.....



My model (quite trivial) is like:

surv.model<-survfit(Surv(day, status)~line+temp, mydata)

My problem comes when I:

plot(surv.model,col=1:4)

The plot shows three main groupings, because temperature affects
longevity in drosophila. The problem is that the colour used for "line1"
at temperature "18C" is not the same for "line1" at temperature "28C",
which I find extremely confusing. 

How can I specify to keep the same colour for the same line across the
plot?

regards,

Federico Calboli
-- 



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Federico C. F. Calboli

Dipartimento di Biologia
Via Selmi 3
40126 Bologna
Italy

tel (+39) 051 209 4187
fax (+39) 051 251 4286

f.calboli at ucl.ac.uk