R: bar plot with two groups, of which one is stacked
bar-chart, grouping, r
Solution
Doing this requires thinking about how `barplot` draws stacked bars. Basically, you need to feed it some data with 0 values in appropriate places. With your data:
mydat <- cbind(rbind(a,b,0),rbind(0,0,c))[,c(1,6,2,7,3,8,4,9,5,10)]
barplot(mydat,space=c(.75,.25))
To see what's going on under the hood, take a look at `mydat`:
> mydat
[,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10]
a 3 0 3 0 2 0 1 0 0 0
b 3 0 2 0 2 0 2 0 2 0
0 0 0 1 0 2 0 3 0 4
Here, you're plotting each bar with three values (the value of `a`, the value of `b`, the value of `c`). Each column of the `mydat` matrix is a bar, sorted so that the ab bars are appropriately interspersed with the c bars. You may want to play around with spacing and color.
Apparently versions of this have been discussed on R-help various times without great solutions, so hopefully this is helpful.
Problem
I've encountered a small problem when creating a bar plot in R. There are 3 variables: ``` a <- c(3,3,2,1,0) b <- c(3,2,2,2,2) c <- 0:4 ``` The bar plot should be grouped by 'a' and 'c', and 'b' should be stacked on top of 'a'. Doing the grouping and stacking seperately is straightforward: ``` barplot(rbind(a,c), beside=TRUE) barplot(rbind(a,b), beside=FALSE) ``` How can you do both at once in one graph?