scienceoss.com » factors http://scienceoss.com useful tidbits for using open source software in science Wed, 26 May 2010 03:34:19 +0000 en hourly 1 http://wordpress.org/?v=3.3.1 Reorder factors for ggplot http://scienceoss.com/reorder-factors-for-ggplot/ http://scienceoss.com/reorder-factors-for-ggplot/#comments Sun, 23 Mar 2008 21:35:45 +0000 ryan http://scienceoss.com/reorder-factors-for-ggplot/ A somewhat contrived example . . . first, illustrate the problem:

library(ggplot2)
ggplot(iris)+aes(x=Sepal.Width)+geom_histogram()+facet_grid(Species~.)

Unsorted histogram
How do we get these histograms to be better sorted? The following will reorder the factor variable, Species, by the mean of Sepal.Width:

iris$Species = reorder(iris$Species, iris$Sepal.Width, mean)
ggplot(iris)+aes(x=Sepal.Width)+geom_histogram()+facet_grid(Species~.)

Sorted histogram
Now the histograms are sorted by the mean sepal width.

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