How can I fill a geom_violin plot in ggplot2 with different colors based on a fixed cutoff?
For instance, given the setup:
library(ggplot2)
set.seed(123)
dat <- data.frame(x = rep(1:3,each = 100),
y = c(rnorm(100,-1),rnorm(100,0),rnorm(100,1)))
dat$f <- with(dat,ifelse(y >= 0,'Above','Below'))
I'd like to take this basic plot:
ggplot() +
geom_violin(data = dat,aes(x = factor(x),y = y))
and simply have each violin colored differently above and below zero. The naive thing to try, mapping the fill aesthetic, splits and dodges the violin plots:
ggplot() +
geom_violin(data = dat,aes(x = factor(x),y = y, fill = f))
which is not what I want. I'd like a single violin plot at each x value, but with the interior filled with different colors above and below zero.