ggplot2中的着色密度图

Question

When I use following code to generate a density plot:

require(ggplot2)
set.seed(seed=10)
n <- 10000
s.data <- data.frame(score = rnorm(n,500,100),
                     gender = sample(c("Male","Female","No Response"),size=n,replace=T,prob=c(.4,.55,.05)),
                     major = sample(c("A","B","C","D"),size=n,replace=T,prob=c(.02,.25,.05,.68))) 
ggplot(s.data, aes(major,..density..,fill=major,group=1)) + 
  geom_histogram() + facet_wrap(~ gender)

I cannot distinguish between categories of "major" by color.

What I want to get is density plot similar to this frequency plot in the sense of colors and legend:

ggplot(s.data, aes(major,fill=major)) + 
    geom_histogram() + facet_wrap(~ gender)

This question is following my question ( here ) which is already answered here .

Answer 1

You can still try frequency plot with facet parameter scale="free_y" :

ggplot(s.data, aes(major,..count..,fill=major)) + 
  geom_histogram() + facet_wrap(~ gender, scale="free_y")