How to enforce ggplot's position_dodge on categories with no data?

Question

I\'m trying to use position_dodge on ggplot to obtain boxplots of two different signals (ind) sharing the same categories (cat). When there is a category with data for one

Answer 1

x of B has no values, so you can add "B", 0, "x" which essentially indicates that there is no distribution of "values" for x of B. The median and other percentiles are zero.

 data<-data.frame(cat=c('A','A','A','A','B','B','A','A','A','A','B','B','B'), 
             values=c(3,2,1,4,NA,NA,4,5,6,7,8,9,0), 
             ind=c('x','x','x','x','x','x','y','y','y','y','y','y','x'))

Also you do not have to add position parameters here, because when you consider x as a factor, ggplot -- geom_boxplot will automagically dodge to the sides.

print(ggplot() +
  scale_colour_hue(guide='none') +
  geom_boxplot(aes(x=as.factor(cat), y=values, fill=ind), 
  data=data,
  outlier.size = 1.2,
  na.rm=T))