基于堆叠条形图的颜色

Question

I would like to have a stacked barplot like 1 but where the color is different for each bar such as in 2 with the stack line.

x<-matrix(runif(40),ncol=10)
barplot(x,legend=c('part1','part2','part3','part4'), col=rainbow(10))

Answer 1

I don't know how to do this in base graphics. But if you are willing to use ggplot2 , it's pretty easy to do. You can for example use the transparency and the color as two distinct things you would like to change. Here's the code I used.

require(ggplot2)
# defining the data
set.seed(1)
x<-matrix(runif(40),ncol=10)
df <- data.frame(x=factor(rep(1:ncol(x), each=nrow(x))), 
                 y=as.numeric(x), 
                 part=factor(paste0("part", 1:nrow(x)), levels=paste0("part", nrow(x):1)))
# ggplot call...
ggplot(df, aes(x=x, y=y, fill=x, alpha=part)) + 
  geom_bar(stat="identity") +
  theme_bw(base_size=30) + 
  scale_x_discrete(name="", breaks=NULL) +
  scale_y_continuous(name="") +
  scale_fill_discrete(name="", guide="none") +
  scale_alpha_discrete(name="", range=c(.3,1))

This gives you the following figure.

Of course you can then change the colors and transparencies at will. Just change the scale_alpha_discrete and scale_fill_discrete function calls.