# [R] How is label parameter used in text() when passing it a vector?

Jim Lemon drjimlemon at gmail.com
Thu Oct 20 23:50:25 CEST 2016

Hi mviljama,
Without knowing what "dta" contains, it's a bit difficult. Here is an example:

set.seed(2345)
dta<-data.frame(age=sample(20:80,50),skin=sample(0:1,50,TRUE),
gender=sample(0:1,50,TRUE),trt=sample(0:1,50,TRUE),
exposure=sample(1:21,50,TRUE),fit5=runif(50))
samp010<-dta\$trt==0 & dta\$skin==1 & dta\$gender==0
library(plotrix)
expcol<-color.scale(dta\$exposure,extremes=c("red","green"))
par(mar=c(5,4,4,4))
# set up an empty plot
plot(x=dta\$age[samp010],y=dta\$fit5[samp010],type="n")
# add the points as text
text(x=dta\$age[samp010],y=dta\$fit5[samp010],col=expcol[samp010])
legend.values<-seq(1,21,length.out=5)
# add a legend for the colors
rect.col=color.scale(legend.values,extremes=c("red","green")))
# label the legend
text(48,0.55,"Exposure")

Jim

On Fri, Oct 21, 2016 at 4:33 AM, mviljamaa <mviljamaa at kapsi.fi> wrote:
> I have a slight doubt with using text() with the label parameter having to
> contain a vector of of integers (specifically integers in the range [1, 21]
> corresponding to factors of my categorical variable that I want to numbers
> to tell).
>
> What I'm currently plotting is the following command:
>
> text(dta[trt == 0 & skin == 1 & gender == 0,]\$age,invlogit(predict(fit5,
> newdata=dta[trt == 0 & skin == 1 & gender == 0,])),label=1:21, col = dta[trt
> == 0 & skin == 1 & gender == 0,]\$exposure)
>
> (it's a plot of a logistic model)
>
> \$exposure is the categorical variable that takes values of integers in the
> range [1, 21]. The coloring seems to work, but I'm not sure whether
> label=1:21 makes it so that it actually labels the point with the
> corresponding exposure level or whether it just walks through 1 to 21 and 1
> to 21 over and over again.
>
> Can someone explain?
>
> Also how can I get the label parameter to put the number of the level of the
> exposure as the corresponding point?
>
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