[R] Densities in legend

[Uwe Ligges]

Daniel En-Wenn Ho wrote:
> 
> Hello all,
> 
> Does anyone know how to add densities of a histogram to a legend?
> 
> I have tried to label five histograms with the following code, to no
> avail -- each time, the legend symbol is simply blank.
> 
> postscript("graph9.eps")
> title=c("Comparison of Quintiles")
> hist(quant1$pre,xlim=c(260,310),ylim=c(0,12),ylab="Frequency",xlab="Cholesterol",density=10,main=title)
> hist(quant2$pre,add=TRUE,density=20)
> hist(quant3$pre,add=TRUE,density=30)
> hist(quant4$pre,add=TRUE,density=40)
> hist(quant5$pre,add=TRUE,density=50)
> legend(260,12,density=c(10,20,30,40,50),legend=c("Quintile 1","Quintile 2","Quintile 3","Quintile 4","Quintile 5"))
> dev.off()
> 

The following will do the trick:
  legend(260, 12, fill = TRUE, angle = 45, density = 1:5 * 10, legend =
paste("Quantile", 1:5))

a) You need to specify "fill = TRUE" to draw boxes beside the legend
texts.
b) You need to specify an "angle" to plot shading lines.

Uwe Ligges
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