[R] Violin plot for discrete variables.

[Liaw, Andy]

I'd suggest dotcharts, such as:

x1 <- sample(letters[1:4], 100, replace=TRUE, prob=c(.2, .3, .4, .1))
x2 <- sample(letters[1:4], 100, replace=TRUE, prob=c(.1, .4, .3, .2))
f1 <- table(x1) / length(x1)
f2 <- table(x2) / length(x2)
lev <- factor(c(names(f1), names(f2)))
require(lattice)
dotplot(lev ~ c(f1, f2), groups=rep(1:2, c(length(f1), length(f2))),
        panel=panel.superpose)

HTH,
Andy

> From: Witold Eryk Wolski
> 
> Dear Rgurus,
> 
> To my knowledge the best way to visualize the distribution of 
> a discrete 
> variable X is
> plot(table(X))
> 
> The problem which I have is the following. I have to discrete 
> variables 
> X and Y which distribution I would like to compare. To overlay the 
> distribution of Y with lines(table(Y)) gives not satisfying results. 
> This is the same in case of using density or histogram.
> 
> Hence, I am wondering if there is a equivalent of the vioplot 
> function 
> (package vioplot) for discrete variables
> which starts with a boxplot and than adds a rotated 
> plot(table()) plot 
> to each side of the box plot.
> 
> Maybee I should ask it first: Does such a plot make any sense? If not 
> are there better solutions?
> 
> cheers
> Eryk.
> 
> 
> -- 
> Witold Eryk Wolski
> __("<  School of Mathematics and Statistics     _
> \__/   University of Newcastle                 'v'
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