[R] Newbie question - struggling with boxplots

[Ista Zahn]

On Tue, Aug 16, 2011 at 5:24 PM, Geoffrey Stoel <g.stoel at hourglazz.com> wrote:
> Hopefully I will not be flamed for this on the list, but I am starting out
> with R and having some trouble with combining plots.
>
> I am playing with the famous iris dataset (checking out example dataset in R
> while reading through Introduction to datamining)
>
> What I would like to do is create three graphs (combined boxplots) besides
> each other for each of the three species (Setosa, Versicolour and Virginica)
> with each graph showing showing four boxplots Sepal.Length, Sepal.Width,
> Petal.Length and Petal.Width.
>
> I can create the boxplot for the total dataset by doing the following:
>
> data(iris);
> boxplot(iris[1:4]);
>
> However I would like to have this repeated for each Species in iris$Species,
> I know I can do this with:
>
> boxplot(subset(iris,Species=="setosa", select = (1:4)));
> boxplot(subset(iris,Species=="versicolor", select = (1:4)));
> boxplot(subset(iris,Species=="virginica", select = (1:4)));
>
> but I am lazy AND I want all three to be plotted besides each other AND I
> don't want to manually type the Species myself.
>
> is there an easier way to do this.... probably yes...

You could use ggplot, like this:

library(ggplot2)
iris.m <- melt(iris, id = "Species")
ggplot(iris.m, aes(x = variable, y = value)) + geom_boxplot() +
facet_wrap(~Species, nrow = 1)

best,
Ista
>
> If you want to help me out... would be deeply appreciated..
>
> Kind regards,
>
> Geoffrey
>
> (new to R and datamining)
>
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>
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-- 
Ista Zahn
Graduate student
University of Rochester
Department of Clinical and Social Psychology
http://yourpsyche.org