different colors for each bar in stacked bar graph - base graphics

Question

I want to plot a stacked bar graph like the one attached, but I want the colors to vary between the categories aa, bb and cc. Specifically, I want the grey blocks in bb to be red and the grey blocks in cc to be green. The following code serves as a simple example and illustrates what I have already tried:

aa=c(0.2,0.6,0.1,0.1)
bb=c(0.4,0.5,0.05,0.05)
cc=c(0.5,0.25,0.1,0.15)
x=cbind(aa,bb,cc)
x #the data
aa   bb   cc

[1,] 0.2 0.40 0.50
[2,] 0.6 0.50 0.25
[3,] 0.1 0.05 0.10
[4,] 0.1 0.05 0.15

default behavior, all blocks have the same color in each categories

col=rep(c("white","grey"),2)
col
# [1] "white" "grey"  "white" "grey" 

barplot(x,col=col)

but I want the grey blocks in bb to be red and the grey blocks in cc to be green

col=cbind(rep(c("white","grey"),2),rep(c("white","red"),2),rep(c("white","green"),2))
col

[,1]    [,2]    [,3]   
[1,] "white" "white" "white"
[2,] "grey"  "red"   "green"
[3,] "white" "white" "white"
[4,] "grey"  "red"   "green"

barplot(x,col=col) #not working

col=c(rep(c("white","grey"),2),rep(c("white","red"),2),rep(c("white","green"),2))
col
[1] "white" "grey"  "white" "grey"  "white" "red"   "white" "red"   "white" "green" "white" "green"

barplot(x,col=col) #not working either

Many thanks for any suggestions.

Answer 1

A workaround: extend your matrix so that values correspond to fictitious categories, with just one color per category. Only one of aa, bb and cc will actually have data in those categories.

> xx <- rep(0,4)
> x <- matrix(c(aa,xx,xx,xx,bb,xx,xx,xx,cc),ncol=3)
> x
      [,1] [,2] [,3]
 [1,]  0.2 0.00 0.00
 [2,]  0.6 0.00 0.00
 [3,]  0.1 0.00 0.00
 [4,]  0.1 0.00 0.00
 [5,]  0.0 0.40 0.00
 [6,]  0.0 0.50 0.00
 [7,]  0.0 0.05 0.00
 [8,]  0.0 0.05 0.00
 [9,]  0.0 0.00 0.50
[10,]  0.0 0.00 0.25
[11,]  0.0 0.00 0.10
[12,]  0.0 0.00 0.15

And plot as you did:

> col <- c(rep(c("white","grey"),2),rep(c("white","red"),2),rep(c("white","green"),2))
> barplot(x,col=col)

Answer 2

library(ggplot2)
library(reshape2)
x <- data.frame(aa=c(0.2,0.6,0.1,0.1),
                bb=c(0.4,0.5,0.05,0.05),
                cc=c(0.5,0.25,0.1,0.15),
                dd = 1:4)
x <- melt(x, "dd")
col=c(rep(c("white","grey"),2),rep(c("white","red"),2),rep(c("white","green"),2))
ggplot(x, aes(x = variable, y = value)) + geom_bar(stat = "identity", fill = col)

Answer 3

This works by adding one coloured bar to the plot at a time:

# white bars 
barplot(x, col='white', axes=F, axisnames=F, yaxp=c(0,1,2), las=1)
cols=c('grey','red','green')

# add coloured bars
for (i in 1:ncol(x)){
    xx = x
    xx[,-i] <- NA
    colnames(xx)[-i] <- NA
    barplot(xx,col=c('white',cols[i]), add=T, axes=F) 
}